I ran marathons, back in the day, during the first running boom. For about 8 years I focused heavily on marathon training. I then seemed to lose my desire to run marathons. This was about when I turned 30. I actually ran my first marathon at age 17. I then focused on swimming and biking for a few years, and ran on and off. I then got back into running a lot and just focused on the 5K and 10K races. I then after time., late 40's, even lost interest in racing. For the past 18 years, I just run only, 40-50 minutes everyday, sometimes on the weekend get a 60+ minute run in.Mostly slow, but mostly progression type runs. Now into my 60's and just run everyday, with no health or mobility problems. Just run, just get out the door. I no desire to go back to the marathon, even though I think about it every now and then.