spells that are activated in "any phase" ... can I really activate them at any time at any phase? or what conditions I have to meet to use them?

Example 1: can I cast "mists of releh" in upkeep phase??? in this way I could know in advance if I can "dodge or not dodge" the monster I chose?

Example 2: can I cast "wither / red sign... / shrivelling" in upkeep phase? and know in advance if I can "fight or not fight" a monster in my movement phase?

thanks for the help...

Spells only last for one phase, so casting in upkeep would do you no good.

On the other hand, Mists of Releh can be used to avoid a monster during movement phase or one that appears during an encounter (Arkham or OW).

Yep, the wording Any Phase simply suggests that in case of need you may cast it at any point of the turn sequence. This is pretty fundamental for the game: an attack spell is usually casted during the Movement phase, simply because most of the time you have to deal with monster, it will happen during movement. But what if a monster appears as a result of an Encounter in Arkham or in an Other world? These encounters happen during a different phase, and so if the wording would have been "Movement phase" you wouldn't be allowed to cast them when fighting monsters in different phases. And this should be a non-sense.

ricedwlit said:

There are exceptions to this. For instance, voice of Ra lasts until the end of the turn, so you get +1 to skill checks in all phases.

ricedwlit said:

How do you know this? I don't think there is any general rule like this. Usually the duration of a spell is spelled out in the spell's description. Most last less than a phase.

mageith said:

I agree there is no default rule - I was thinking mainly of the spells that were listed in the original post. Mea culpa.