I currently have a 3 month sub going, but I'm not playing a ton because I got temporarily pulled into some other games (Starfield, Dead Space, Diablo 4). I let my sub go quite frequently, I simply stop paying when I find that I'm not playing for 'x' amount of hours a month, say 15 hours for example. My general $/h value is $1/h and if I'm not getting that, I start thinking "is it worth it?".

As for what it would take for me to stop subbing completely? hmm..the game would have to change dramatically, as I'm casual enough to still have months if not years worth of content left to do, and they're still bringing out new content that I enjoy.