Old Pokemon TCG returnee

[Steener]

So I havent played in years and recently started playing online to get the hang of things again, and have enjoyed it. I was wondering if I were to buy real packs what packs are the ones you can use in tournies and such? And how often are cards not viable in decks anymore? And what packs should I not get if I would wanna compete?

 

[Astinus]

Here's the list from the Pokemon Company about the 2016 rotation. They update every year as old sets are taken out and new sets are put in. And they announce in plenty of time to allow players to prepare for the change. This is the rotation that the official tournaments follow.

This doesn't mean that you need to always change your decks. You can find players who play under the Expanded format, which is also listed on that page and starts with the Black and White set.