We usually just put it on if they need to sit and rest (if we've been out all day) or if I need 10 mins to have a shower. Or if I really need to get some stuff done without interruption and they are too antsy to play by themselves. Sometimes it goes on at mealtimes if we're not in a rush, but often it just goes back off again as they forget to eat!
So I really use it as a tool rather than entertainment, I used to feel guilty about it but then i got PND and when i really wasn't coping i needed it to take the load off of me. Now we have a good balance of free play, outings, play dates, playgroup, Kindy etc.