I think you can really safely say that unless you're breeding and/or standing the stallion, you really don't need one. And I'll even go as far as to say that a lot of stallions who are currently being bred, really don't need to be. As far as ownership goes, unless you really are an upper level COMPETITION rider, you don't need the extra "fire" that a stallion brings to the ride if you're not breeding. I prefer to ride stallions and then mares, but I'll be the first one to tell you that if I were to quit breeding I'd either geld or sell the stallion. They are a logistics problem EVEN when they aren't a behavioral problem and goodness knows, any one of them can become that in a hot second.