No I never wear bra when sleeping, it is very uncomfortable. In fact even if I am in the house all day I never wear bra, I find it very uneasy especially when I am doing household chores, it only add to my discomfort.
Bra's are good when you are going about your daily activities. They help the clothes look good on you. They help them to stand firm. However when I go to bed I just want to be comfortable, so the bra has to come off.