I probably average about once a month. A century is not a big deal to me and I don't keep track of how many I've done. A double century I consider challenging...not only because of the distance, which I can do, but because I have to ride through NYC (twice) to get anywhere that I can ride that sort of distance. I don't mind riding in the city, but riding all the way through it twice on a 200 mile ride sucks.