Having a vfd means I will slow down the rpm for a big holesaw with. the twist of a knob. I probably would not bother if I had to change belts. That means tools last longer since they do not run too fast and burn the edges.My dilemma is whether or not I actually use my DP enough to justify a very nice keyless chuck whereas. Or even to upgrade to a variable speed DP for that matter.
A used three phase Dp is normally cheaper and better built then a single phase one of similar size. A one hp vfd is under $75 these days.
BilLD