Shaft Seal Leakage

[sailorboy1]

My shaft seal isn't one of those fancy units with the tube, just a bellows and rotating ring. It wasn't leak much, just a small amount of spray coming off it while the shaft is spinning, but it adds up to a gallon of so after a few hours. I don't think it leaks when not turning, but am checking into this more.

So the question is: if you don't have one of the "drip less" shaft seals how much leakage is normal?