My number is about 50 games. And I would prefer 100 games.
I don't think you can get a good feel of the play with any less than 20 plays.
I only have one game at home and if I get bored, then it sucks.
So I try to find one that I really like.
On the flip side. After I play a game about 2000 times, I trade it for another.
I've never kept one more than 2700 plays.