PokerStars Casino promos are hit or miss for me

I get PokerStars Casino promos on and off and can't work out what changes. Last month I got a blackjack reload, free spins, and a small opt-in promo over about 10 days. They were decent enough, especially the one that gave something back. This week there's been nothing in the casino tab.

I played live dealer blackjack 4 nights the week before, mostly 5 or 10 a hand, around an hour each time. I didn't keep track of the next week, but I played about the same amount, maybe a bit more. The promos stopped showing up after that (or at least I haven't seen any).

Anyone know if PokerStars spaces the promos out by account, or if they just show up randomly? I'm trying not to chase them and just keep it steady, but it is HARD not to notice when they dry up out of nowhere.