Well, I'm still floundering about in retirement myself - but I did want to comment that if you're interested in a fitness career, I don't think you should see your age and arthritis as a detriment there. On the one hand, "senior fitness" is exploding - my gym can't find enough teachers to do the always-packed Silver Sneakers classes - and on the other hand, not too many trainers are well equipped to deal with masters athletes who may have anatomical and degenerative limitations, but still want to maintain a high level of competition. Depending on your level of education in the field it might take a lot more education to get there (personally, the more I learn, the more I realize I don't know, and the less equipped I feel to teach ) - but if you're interested, I wouldn't categorically rule it out.