All year, I've trained for one mountain: Grand Teton. Now that I've reached my goal of climbing the Grand, will I maintain my fitness any longer?

I can be very driven, obsessive even, in pursuing goals. But in the absence of a goal to dedicate myself to, is there any reason to suffer, I mean, exercise? Other than this anomaly of a year, I never exercise. I have no intention of ever doing hill sprints again unless I'm being chased by a moose.

It's ambiguous how I'd determine whether I'm maintaining equal or greater fitness. Appearance and weight are irrelevant; what matters to me is ability. When I was training I tracked metrics I needed to hit, like time per thousand feet of elevation gain. Maybe my friends can ask to hike at any time and put me on the spot, so I don't have time to prepare last-minute? And if at any time I fall below my current fitness level, I'll immediately resolve to no. I'm open to suggestions for resolution criteria!