Does anybody know if you can spend advantages from casting magical spells to recover strain as you can on combat checks?

Since the RAW indicates that the strain is suffered after the spell casting action I wouldn't expect this to do anything for you if you cast a spell while at full strain, but it would make spells from that point forward cheaper to cast if you can generate at least 2 advantage on the checks. Effectively the 2 advantage would recover the strain already suffered, and then you'd suffer 2 more as a result of the spell check.

I have players that are concerned about burning out of strain real fast as casters and this would seem to be a logical solution, but I can't find anywhere that indicates this would be overpowered or not.

If its one of those, not really specified in the RAW things, how are you guys running it?

It's not specifically addressed in the CRB, but here's my way of thinking on the subject:

1. Advantages on any roll can be used to recover strain.
2. The strain for casting a spell does not occur until after the dice are resolved.
   
   Therefore...
   
3. Advantages rolled on a magic check can be used to recover current strain, but not to recover the strain from that specific spell.

So... if a wizard starts an encounter with zero strain and rolls on their first arcana check, they cannot use the advantages to recover strain, because they do not yet have any. Once the roll is resolved, the wizard suffers 2 strain. If he rolls on his next arcana check, he can use those advantages to recover strain from the previous check, but still suffers 2 more strain after the roll has been resolved.

20 minutes ago, Ryckarde said:

Does anybody know if you can spend advantages from casting magical spells to recover strain as you can on combat checks?

Since the RAW indicates that the strain is suffered after the spell casting action I wouldn't expect this to do anything for you if you cast a spell while at full strain, but it would make spells from that point forward cheaper to cast if you can generate at least 2 advantage on the checks. Effectively the 2 advantage would recover the strain already suffered, and then you'd suffer 2 more as a result of the spell check.

I have players that are concerned about burning out of strain real fast as casters and this would seem to be a logical solution, but I can't find anywhere that indicates this would be overpowered or not.

If its one of those, not really specified in the RAW things, how are you guys running it?

It's not OP, go ahead and let your casters. Mine is constantly Strain starved. I make spells in trees though, and some cost more than 2, but still, he is constantly in a pinch over Strain.

@Simon Retold has it right, you can use to recover current strain, but you don't suffer the spellcasting strain until after the roll has been resolved.

45 minutes ago, Ryckarde said:

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I have players that are concerned about burning out of strain real fast as casters and this would seem to be a logical solution, but I can't find anywhere that indicates this would be overpowered or not.

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If they're concerned about burning out of strain, that's where talents come in:

• Desperate Recovery (CRB73) gives you +2 when rolling to recover if you're at or over half your threshold
• Second Wind (CRB74) is a ranked talent that lets you recover [Ranks] of strain as an incidental once per encounter
• Heroic Recover (RoT88) lets you recover strain equal to [choose one characteristic] ranks once per encounter as an incidental (costs a Story Point)

Granted, RoT doesn't have Second Wind listed as an available talent, so I'd be weary of allowing both that and Heroic Recovery, but YMMV.

The Rejuvenation Secondary Effect for Heroic Abilities is another great way to recover some strain right when you probably need it. Also encourage the Charming Face character in the group to get the Encouraging Song talent!

But definitely spend those Advantage on recovering Strain, you definitely need it.