At least a few days a week, decide what course you’re going to run, and then leave your watch at home. Other days, run wherever, guided by total time on your watch. The thing to mostly avoid is timing yourself over the same courses day after day. That way lies the madness of beating yourself up for running slower than you “should” or forcing yourself to pick it up because you’re 6 seconds slower at your 45-minutes-into-it checkpoint than you were yesterday.