why after 16 years do I seem to know less than when I started?

How important is it to continue using 40 bucks a litre Petit paint?
Are there any shortcomings to fast dry primer?
What about the gallon of good quality oil based house paint primer I have?


A friend works @ Benj Moore and virtually gives me my house paint
How different is it?

Tried Interlux, seemed to be like milk with not much to it?