How long do you let baby stay in the swing/rocker?

I have a mamaroo electronic rocker and ive been putting my baby in it while i do things around the house. The only thing is, i feel guiltt and constantly get the urge to take her out, hold her, change positions, do tummy time, etc. she rarely sleeps in it (in fact she rarely naps at all)...so how long can they really be in those things?