I used to be regular but erratic in exercise patterns, but it was frequent enough to do some good. That's the key: some good. There are many uses to exercise.
Hiking gave me the stable, mind-wandering, one-on-one (or alone) kind of mild exercise I needed.
Swimming helped me feel better about my body's appearance with the same benefits of mind-wandering and sometimes having the company of a friend.
Then there are the more active, energetic sports that I explore occasionally. The more energetic, the less frequently I spend time on them. Anything that can be done with one other friend is sure to be utilized.
I finally took a class in cardio and strength fitness. It was actually the perfect combination of positive reinforcement, minimal equipment, mild frequency, regimentation, motivation, and long term effectiveness. (Never mind that only 3 out of 10 students were male. Definitely a far-cry from being on a basketball team, but it can't be denied that this was basically what I needed.)