Lowering crib mattress?

How old was DC when you had to lower the crib mattress? All of a sudden DS seems to be attempting to pull himself up with the bumpers and front rail. Obviously its time to move it down but was wondering if you left the bumpers in when you dropped it or took them out. We initially took the bumpers out but now he is sticking his arms and legs out and its making me nervous.

If you use bumpers (I know all the reasons why its controversial) did you leave them in when lowered?

Thanks!

Re: Lowering crib mattress?

i lowered it when DS started sitting up in his crib--don't remember how old he was.

i still use the bumpers. i told myself i would reevaluate the situation when DS started rolling over, and i decided to keep them in. he's had some falls from standing in his crib and the bumpers saved him from hurting his head. they're staying in until i see the need to take them out.