When is just one enough?

Would you be happy with one pair of scissors? One frying pan and one pot? How about one car for the family? Or even one vacation a year?

I've been thinking about where in my life "just one" is enough. I go to the gym two times a week. Exercise clothes now are easy to hand wash and dry in a short time. One set of exercise clothes for each season (fall/spring, summer, winter) plus one jacket is enough. When I take walks I wear the same clothes I wear at home generally so that is all I need to exercise.

I'm not sure where else in my life "just one" is enough but I am thinking about it!