What you need to ask yourself is, how do you feel when you log in? Is it dread? Happiness?

If you feel bothered by having to log in or do things, then it is time to quit the game. If it still holds some addictive grip on you and you like logging on to roll the gacha and spend stamina/focus then keep playing.

Once that question is answered you can look at the above replies if you want to keep playing.

Personally i will quit the moment i have used up all my event tickets. Ever since FKG launched and even before that i started feeling dread over having to log in. Everytime was "oh dear, i still need to do THAT today..." so i knew it was time to quit.