Hiyas:
I'm confused about this, per the RAW, when do the Acolytes can spend their hard earned xp?
At the end of each session (within reason & common sense)?
At the adventure's terminus?
Or whenever (in the middle of a session (again, within reason & common sense)?
Thanks!
L
Uhh, its not .. Strict RAW kind of thing. You are assumed to spend exp at a per session rate, and some ancedotes within the RAW back it up, but its not specifically stated. Its really a GM fiat kind of thing - I personally like to just openly let people apply their exp between sessions, but some GM's will restrict what you can access. If you want to apply exp on a per adventure arc basis than you are free to do so, but the problem inherent with that is its likely characters are going to spend large amounts of exp, making huge jumps in power levels.
But yes, arguably some talents are weird to spontaneously manifest. Honestly though just decide what works best for you and your group.
I'd say most of the time XP gets spent around our table at the beginning/end of a game session (before or after "the action" for that evening.) Usually after.
That said, if a player came to me mid-game with something he wanted to buy - and a really great explanation for how the character got it right now - I would be more than happy to let him buy stuff immediately. I might even make a role-playing scene out of him training/shopping/whatever to get the new purchase.
IMHO, RPGs are one area of gaming where RAW should not be king. Regardless of what the book says or doesn't say, the GM has, and should be encouraged to exercise, the ability to overrule it in favour of doing something cool or exciting with his game. The best games I've ever run or played in are the ones that don't worry too much about the rules (but also have a GM who's prepared to say "no" to random bull that doesn't belong.)
I allow XP expenditures at the end of my sessions or in-between sessions for the most part. The one rule (yes, it IS in there) that I enforce is that the player informs me of what they are intending to buy with their points. In most cases I agree and they make the changes to their character sheet. There are certain times when I will require that a certain purchase instead wait for the end of the mission so that the propper training can be arranged (Such as learning Pilot (Starship) for the first time, for example). Generally speaking if it is in their character's career tree on the path they have followed then I am pretty generous in letting them pick up the skill or talent, especially stuff the character "should" know, but points or the location of training on the advance tables has confounded them. I am also alot more accepting of upgrades if the player tells me in advance that the character has been pursuing opportunities to train the skill/talent in question and gives me a reasonable recount of how they are going about it (For example, the character is 300xp shy of learning some new thing, but they still go about seeking training. If I hand out 400xp in the next session but they are still "in mission" I might authorize the upgrade at that time.) For continuity's sake the sudden burst of knowledge (and it's previous lack) must not have been an issue in the earlier session: "Why didn't you mention you knew how to pilot a shuttle when we were back at the bloody shuttle?!" In some cases (Tech Priest and Adept being the most obvious) an advance on the XP chart represents gaining a new cybernetic implant and the training to utilize it properly, and for obvious reasons these must be done either between missions or actually gained during gameplay (Magos modifies a cybernetic part to create a hidden storage space in a handy laboratory, thus justifying someone buying Concealed Compartment trait).
Elite Advances by their very nature I handle on a case-by-case basis.
On one occasion so far I have allowed a character to spend XP in-game. It was something the player was planning to pick up anyways, he had the points unspent, it was totally fitting with the character's style (an important factor for me!), plus it was just something cool! In this case it was our team's Assassin picking up the Leap Up talent... During a dramatic death-match duel he was fighting so that he could win the freedom of a fellow acolyte after having just burnt a Fate Point to survive a large caliber gunshot to the head: So the "dead" assassin suddenly leaps up off the floor like an avenging spirit, duster flapping like a cape, nursing a profusely bleeding head wound while both of his pistols spat defiance! Yeah, I approved that XP expendature...
Likewise I generally approve those "duh" upgrades: Sanctioned Psyker wants to buy Forbidden Lore (Psykers).... Guardsman wants to buy Common Lore (Imperial Guard).... A character who is a member of the Cold Guild wants Common Lore (Underworld)...
GLARING EXCEPTION: I only allow a character to Ascend in between MISSIONS. Granted, they can still spend earned XP on things they have access to from rank 1-8 and any Elite Packages they have access to, but the transition into their ascended career is not just a *DING!* "Oh hey, Bob just made Inquisitor! Gratz, man!". On the positive side, they will have more points to spend on those rank 9 lists if they break 13k spent in the middle of a mission.
In DH I would most likely only allow it between sessions. In some games (like Exalted) I have allowed the use of xp mid session or mid fight, since the over-the-top feel of those games makes it fitting that the hero, when hard pressed by a vicious opponent, suddenly unlocks new powers. In the grim darkness of the far future it would make a lot less sense.
It seems that my group is the exception in that I only grant XP after the mission, which is often after some 3-4 sessions. The players also spend their XP after missions. This allows me to grant XP according to how well the mission went, how well they roleplay and so forth.
To make campaigns work I usually break them up in several missions, awarding XP after each one.
True, this practice sees me handing out more XP at once than I would if handing out on a per session basis. My players seem happy with this practice since they feel like they "level up" properly after a mission. Granting an additional sense of achievement.
Storhamster said:
It seems that my group is the exception in that I only grant XP after the mission, which is often after some 3-4 sessions. The players also spend their XP after missions. This allows me to grant XP according to how well the mission went, how well they roleplay and so forth.
To make campaigns work I usually break them up in several missions, awarding XP after each one.
True, this practice sees me handing out more XP at once than I would if handing out on a per session basis. My players seem happy with this practice since they feel like they "level up" properly after a mission. Granting an additional sense of achievement.
I tend to hand out more XP at the end of missions for the "Well done, mission complete" thing. Less successful resolutions would earn less or no bonus. The idea of handing out XP at the end of each session is that you are measuring out a reward for things that they have done in that session while it is still fresh in everyone's mind. It also serves the role of carrot on a stick, in that if a player misses a session they miss that session's XP award, instead of just getting the group's lump sum at the end. It also means that if I hand out less XP for a session that was a bit sloppy and off the mark then the group has that immediate feedback of "we could have done better there". Even if I am going to be stingy about letting them actually spend any of it that session I still like doing the on the spot awards. It also meshes well with my post game feedback and kudos session where players can nominate each-other for especially awesome scenes or RP moments, possibly earning a token XP bonus for the nominees.
For me and my group...
XP only to be spent at the start or end of a game session.
Generally I give out each session but sometimes I alter that (against the RAW)...
This obviously varies from GM to GM. I do not award XP until specific breaks in a mission; such as the Chapter Breaks in the published adventures. I also, like Zilla stated, require players to inform me of what they intend to spend their XP on, and that it receive my approval. I also keep my own copies of character sheets so I know what is what with the PCs.
On topic and in short;
-=Brother Praetus=-
I personally do it at the end of each adventure (usually every 2-3 sessions) as it makes it easier for me to work out (i also do bonuses for really good roleplay, special objectives etc). just the works best, never thought of doing it every session.
I prefer a subjective fast and loose version of XP spending. Generally speaking, if your not locked in drama time now, you can spend on basic skills, but talents and advanced needs to wait until down time. Think of it as the "adventurer's bag" only for skills and such. Metaphorically, you can buy rope and a waterflask, but not a flaming greatsword. Shaodwing because you plan on tailing someone later tonight? Sure. Lightning strike because the ork Warboss is coming over the ridge? No.
I find players tend to buy things related to the session if you give it out at the end of that session, which in turn leads to more believable characters. I also try to give an elite advance option at the end of each session, such as INquiry if it's been an investigative game.
Plus, it's nice as a player to advance your character regularly, and it feels like more of an investment if you have to save up for big spends. Why take away that opportunity by making them spend their XP in big lumps.
This of course comes with the caveat that nonsensical advances have to wait (such as the cybernetic implants someone else mentioned).
vs
Storhamster said:
It seems that my group is the exception in that I only grant XP after the mission, which is often after some 3-4 sessions. The players also spend their XP after missions. This allows me to grant XP according to how well the mission went, how well they roleplay and so forth.
To make campaigns work I usually break them up in several missions, awarding XP after each one.
True, this practice sees me handing out more XP at once than I would if handing out on a per session basis. My players seem happy with this practice since they feel like they "level up" properly after a mission. Granting an additional sense of achievement.
Nope you're not the only one. I hand it out after a mission, or if it's a long adventure I'll hand it out at a suitable break or chapter end if it's a prepublished. Also instead of gettting the starting 400 XP I've reserved that for awarding players with skills that frankly fit in with their character as things they should have or reflect what they've done.
Likewise with others here I've allowed advances mid game on rare occasions if it's one the player had told me they intended buying and it comes up they need it there, I'll grant them the skill and deduct the XP they next recieve.
I'm also kinna strange on fate points only restoring them after in game resting. Though it usually works out every session anyway. 
Generally I only allow players to spend XP between game sessions, and only increasing existing skills or acquiring new talent types (or getting logical upgrades to existing talents). Getting new Advances skills usually only when players are between missions; these usually span at least 4 or 5 play sessions before I let them get to a point where I feel their acolytes have an opportunity to have some "down time" to study new skills. I usually don't sweat Basic skill acquisitions however (like dodge or something obvious like that). I like to encourage players to make thoughtful XP investments keeping in mind their next mission.