I'm 68 and got back into riding 5 years ago. I was riding 7 days a week but cut it down to 6 days a week (weather permitting) at the beginning of last year. Living in Florida, we have year round cycling and last year I rode 9,600 miles and never had a problem from too much saddle time. Just listen to your body and don't push it when your body is telling you not to. If your body feels a little sore, take the next day off.