I usually play most days - after work it would be in the evening; even if I have had stuff on and it is just before bedtime I usually squeeze a couple of games in.
The fun is when you have that game where the ball just won't go down and you end up with a high score! Recently did that on both Dirty Harry (finally completed a crime wave) (a modest 2.8K million for a five ball game) and Mousin' Around! (15 million - that's starting to get up there for three ball fairly high difficulty).
I love playing pinball, it is just heaps of fun.