I've had a LOT of games twice. I don't really understand the question, honestly. If pinball is your hobby, any game is worth owning, buying, fixing up again, selling... whatever your desire. I have had High Speed and Secret Service the most. I think I'm up to having had 3 or 4 of each of those now.
Same time... I've had two of the same game, at the same time, something like 8 times.