How big is too big?

My daughter stopped using hers at 6 months, but I think people usually put their babies in cribs earlier than that.

When baby reaches the weight limit of the bassinet. Ours is 15lbs

I stop using it when they start to roll over, about 4-6 months.

I takem out when theyre too heavy for them lol when they kick n shake the whole dang thing

It is ad much about size as it is about milestones. You shouldn't use a bassinet if your child can roll over.

yeah my little man is kicking and rolling and i got afraid so i just let him sleep in his crib now.

thank you everyone

Probably about 6 months.

I never used one.  My daughter went straight to her crib. 

Rolling over is a sign he needs to get to a more secure bed that does not move as easily.  I think dd was about 6 months or so when we transitioned to a pack n play.