Once per turn abilities

[drezzinator]

Some abilities say once per turn. It makes sense that abilities like Gardevoir's Bright Heal (AOR #54) have this text, but I have several follow up questions:

1. What happens if Gardevoir leaves play and then enters play the same turn? Can I active Bright Heal, return to hand, play to bench, then activate Bright Heal again?
2. Abilities/Poke Powers like Unown's DARK (Undaunted #40): Can I play him, return him to hand, then play him again and active DARK both times?
3. What about going to the discard pile then back into play? Can I play Unown (AOR #30), activate Farewell Letter, replay him via Revive (BW #102) and then activate Farewell Letter again?

 

[PokePop]

There are two types of text to look for.
One is the most seen and is "Once per turn you may..."
That restriction affects only that Pokemon while is remains in play and no other Pokemon with the same Ability. Once the Pokemon leaves play, that restriction does not follow the card as it moves from one zone to another.

The other type of text you will see is "You can only use one [Ability name] per turn".
That affects any and all Abilities that have that same name, regardless of whether they are on different Pokemon with the same name, or even differently named Pokemon.

So, for your specific questions:

1. Yes
2. Yes
3. Yes