The 'supply house' has an advantage to those of us who do comm/ind work. Yes, big box probably will beat $$ for resi mat'l but.....what about what they don't have?
Also, the supply house account is net 30, sign & drive. I guess some of us remain loyal to the supply houses.
As to WWG....when the supply house doesn't have it, or can't get it in a reasonable time...ya pay the price. 24 hr emergency works at WWG, and net 30 accounts also. And as a bonus, parts for a whole lot of things.
