Every healthy retiree should have a home-based business ...
it seems to me.
At least in Canada.
It allows you to claim part of the cost of telephone, computer, probably internet, some office supplies, auto operation, etc. against any income. Need to keep records - of expenditures, and of activities undertaken to promote the business, people consulted, etc.
Income tax people allow one to run losses for a few (usually about three) years if you can show them that the business is legitimate.
In Canada, part of cost of home maintenance, e.g. if use a room exclusively for business, a proportion of rent, tax, etc. also cost of heat, light, water, etc. agaist income from the business.
But Canadians need to be careful about claiming part of mortgage, as capital gain on owner-occupied home comes with no tax liability - but if you claimed deductions on part of home purchase, that made it partially a business establishment, so would likely cause trouble when you sell the home.
Surely you have some skills that you could offer to businesses, groups or individuals.
Have a great week, all.