My windlass is over 30. Every 10 years or so I have to open it up, clean the clutches and regrease a few parts and put it back together. Still runs great.
What's wrong with yours?
Depending on the unit, I'm not sure the ones they make now are any better than what you have. If yours was only a rope and you'd prefer a rope/chain unit, now might make sense to make that change but if the one you have does everything you need and it's still in good shape (plating, paint or stainless is in good shape) I'd look into getting it fixed.