okay when exactly do you have to declare when you use a team ability and how long(especially with wildcard and the batman stealth) does the effect last before you have to declare it again?

thanks in advance

For WCs, you declare which TA you are copying in response to any declared action. As long as the change does not make the action illegal, you are fine. You keep the TA until you change it to something else (including changing to copying nothing) or the figure(s) you are copying from are no longer there.

For regular ones, they're just there. They all do different things at different times, so you can't really say that TAs in general are on or off at X time. The TAs themselves pretty much describe when they work.

From 2010 rules, page 16
A wild card begins the game not using any other character’s team ability. A wild card may change the team ability it is using (or choose not to use a team ability) to any team ability possessed by a friendly character when an action is declared by any player but before the action begins.

This is tempered by the new TA not making the action illegal

Same page
A wild card retains its most recently used team ability until it uses another team ability, chooses not to use a team ability, or until after the resolution of an action during which all characters whose team ability the wild card is using are defeated or removed from the battlefield.

well for regular abilities, they are considered active unless otherwise turned off.

Batman has Bat TA. in stealth, he's blocked from range. Now, if on your turn, you want to Perplex or PC him, you'd have to turn it off, meaning your opponent could also see him. At the end of your turn, the TA is considered back "on".

For the record, and this may be getting too complex for the OP's needs, you don' have to cancel the Batman TA to do this. He can use Stealth. This also means that he can choose to not use Stealth. The result being that he can opt o not use Stealth while still keeping his TA active. He'll be Stealthy again on the next action, not the end of the turn.

actually, this is exactly what i needed to know for batman TA, thanks

I have a semi-related question that came up in last night's game;

When would a figure that can choose to be a giant via an SP (Uncle Sam, specifically) be required to declare whether he is exercising that option during an opponent's turn? Can it be at any point, or only in response to a declared action (same as wildcards)? If the latter, I presume your opponent would need to declare what action they were taking specifically...

The timing is the same.

There is no rule saying a power cancellation cannot be done if it makes the action illegal, as there is for WCs. That said, if a judge ruled similarly to the WCs, I'd have no beef with that.