Been retired 15 years. Make sure you have all the areas covered: cultural, educational, physical, creative, charitable, etc.

We found regular exercise, whatever you prefer, is really needed in retirement.
Charitable activities can cover many aspects of retirement. My husband gets physical activity from his Habitat work, social needs from the groups of guys he regularly volunteers with and creative mind use from thinking of new ways to do things and working out better systems.
Keep your mind exercised by any means you like.