Depends on situation but I doubt most home-made machines are capable of working the motor to full rated output anyway. I use 2.2kw spindle and VFD because I get an ER20 collet that way for 1/2" shank cutters rather than its power. I think most VFDs are overload protected; maybe not against dead short but ok against modest overload. My setup is around 5-6 years old now and still going strong.