when is a good time to get aHV oil pump?

I once used HV pumps or a heavier/shimmed spring on most of my cars since the old Direct Connection books recommended it, but they always seem to cause leaks in my engines, especially at the rear main seals on the big blocks. After talking to a lot of machinist the consensus was they`re not necessary so now I don`t use them. I agree with most of the field that they`re generally not needed.