So I did some pulls, and played for a few days, got 3000 gems from a bingo thing. And there's just the Dawn banner thing up atm, and I already got a Dawn from it (my 3rd pull ever)
I wasn't sure how often new banners came up and if I wanted to save or not.
Save for when there's a Poke Fair. Massively increased rate for 5 star characters. Alternatively, save for when Sygna Suit Red gets focused because he's by far the most powerful Sync Pair