Long term fixed income tenants

[Joshua Bailey]

Looking at a duplex that has 1 unit with 2 retired long term tenants (since 2000). I was told they mow and snowblow so he doesn't pay someone to do it. They are paying 200-300 below market. I would like to raise them slowly, maybe $50-75 in the first 90 days. The other unit is mostly updated, but theirs hasnt been touched since they've been in it so long. Would you raise rents on these folks who have a fixed income or just leave them be?