I will purchase any game that I see value in. When my collection is at capacity, I purchase pins if I feel the new purchase will bring new value to the collection. By value, i am not referring to financial value, rather entertainment value. Financial value is important, as I will not make a purchase that I expect value degradation greater than 20%
Pinball to me is tying up liquid capital to "dead money", experiencing the game, then reviving the money +/- at the time if the sale.