This isn't to sound flip. I have so many hobbies and interests the thought of what to do if interest in one wanes has never crossed my mind. Church and doing a lot of music and teaching there consumes a lot of time. Gardening, sailing, hunting, shooting for fun, pleasure and competition, reloading and casting bullets, restoring bamboo fly rods, tying flys. I sitll enjoy downhill and XC skiing but at almost 60 those 10 mile ski trips are a thing of the past, dinking around with my vintage sports cars and reading and studying about all the above.