A thousand bucks is basically the cost of learning that lesson though.

I don't know, man, "just listen to the cut" sounds like something my grandpa would say and then end up with a broken endmill and a scrapped part. I get that 30 years on a Bridgeport gives you a magic ear, but what about when you're running a brand new machine with a different spindle taper or some garbage Chinese insert that sounds happy for two seconds then explodes? Charts at least give you a starting point that's been tested by someone who isn't trying to prove how cool they are. Did you check the chip load after you got that nice finish or just assume the old guy was right?