Sleep sacks?

Rachel

How many of your babies sleep in a zen sleep sack? And if so do you have other types that you switch back and forth with? Does it make any difference if you constantly switch or should they get used to one particular sleep sack style? I have a halo and a nested bean one that I interchange cuz ya know, laundry is a pain . Anyone else have any similar situations has it made sleep better/ worse? Thanks !