If I am renting a thing I expect free repairs forever and they should expect to hear from me any time my rental devices is not doing what I expect it to do. If that is not included in the rental fee then I need not use that device and they should expect it returned covered in animal feces.

Exactly.

If I am renting it, then anything goes wrong, they either fix it immediately on the spot, or promptly swap it out for an equivalent unit.