How much to reduce monthly rental rates on home if tenant performs home improvements.?

A prospective tenant asked if I would be willing to lower the monthly rental on my home in exchange for performing some home improvements. The rent is currently $1,500/month and I'm wondering what experiences other people have had with this arrangement and how much to reduce their rent for these services. Some examples are replacing flooring in the bathroom and kitchen with tile, repairing drywall damage, and hanging new interior doors.