I take mine until I start forgetting. I don't forget on purpose. I dont' know why I have this problem but it's not just bipolar meds but all meds and vitamins. Birth control, too, which is why IUD is good. Even anti biotics and pain meds when I need them, I start to forget pretty quickly.
So far 7 for 7 with my lithium this time.
But tomorrow I won't take it, maybe not for the weekend, due to my surgery.