What is Normal? What is Sane? It's all your own perspective really.
I would say it seems to be a factor of Interest, Time, Space, and Money. The more you have of each the larger your collection can grow.
Only a starter here, first a gift Phalaenopsis, and second a cheap but pretty Dendrobium. So grand total 2 after 3 months. Obviousley I Plan to get more. I Have much Interest, but lacking on the other three counts.