Me and Falco77 had this argument but does Once per turn mean once on either player's turn or once on the player who controls the card that has the once per turn effect's turn?

Ex. I had Junk Archer out and with his effect (Once per turn I can banish a monster until the end phase) could I do that only on my turn or on either mine or my opponents?

Junk Archer's effect to banish is an Ignition Effect, which can only be activated during the controlling player's Main Phase 1/2.

I believe he wants to know how the Once per turn effect works.

It's like this: If a monster has a once pr turn effect and you choose to activate it, even if it changes the sides of the field during the same turn you will not be able to activate it again. The once per turn conditions applies for both players on both sides of the field. If the monster leaves the field however (EX: being send to the grave after using it's effect and then brought back with Monster Reborn, it will be able to use it's effect 1 more time).. Also when you end your turn and it's your opponent's turn the monster gets to use it's effect once again but only if it allows you to use it, otherwise you have to wait for your turn to activate it. That means if your opponent mind controls such a monster he can use it's effect in his turn.

Unless stated in the card otherwise (Formula Synchron if you will) the ignition can only be activated as chain one within priority either during your main phase 1 or 2.If "once per turn" is stated.. Well you can do this only once a turn ( the entire turn, so 1 time both Main 1 and 2)

What about Dark Smog? I heard you can use it on either players turns..

the card should state during eaither players turn if it doesnt you can only use it during your turn

what DE said

Locked

only on your turn.