I do it when it's winter and I cba to remove the frost, also whenever I wash my car to keep dirt away. Summer there isn't a lot of point for me, maybe when a storm is coming up with hail. Our's doesnt have a remote or a motor to open it for us so it can become kinda annoying.
look at all these 3rd worlders without a garage wtf
Edit thanks to nelu: we now have a motor with remote PogU
Sometimes, my step-dad usually parks in there cus he's got the most expensive car and has keyless so dont want it to get robbed, usually just when we go on holiday