Don't get old and rusty, just get old.

Just because you're getting old, doesn't mean your career has to taper off. Like Napoleon Hill mentions in his book Think and Grow Rich, most of the richest people in the US made the majority of their money in their 50s.

I believe one of the best ways to accomplish this is to stay relevant throughout your career. Always stay hands on in whatever you do. Continue to get your hands dirty even as you move into management. You will grow stagnant if you do not continue to view the problems at eye level and dream, create, and solve.

In all the interviews I've done with executives, this seems to stand out as one of the most common themes among the successful ones. So as you get old, don't forget where you came from.