With people living longer and striving for earlier retirements, the very definition of retirement is evolving. No longer is it merely a way to stop working and basically wait for death to come; that would take too bloody long and be a bore. Now retirement takes many different shapes and forms:
Starting a new business
Part-time consulting
Travel
Volunteering
Reading, writing, resting
Getting fit
Watching grandkids
Farming
Gardening
…whatever you can imagine and whatever you want.