Something I like to do mainly after washing the bike then parking it or riding in cruddy weather, is to gently with your thumbs on the piston area of the callipers push them in. They should slide easily. I find it clears the muck off a bit to stop it building up in the one spot as they don't actually move a lot in normal use. I haven't had a stuck brake yet touch wood. It is also a good indicator if a bit of lubrication is going to be needed. Hope this makes sense & helps.