Dropped $180 on a Boss brush last spring and it paid for itself on one nasty job in Aurora
I was doing a sweep on a 1920s bungalow in Aurora and the flue was caked with glazed creosote that my old poly brush just smeared around, so I grabbed a Boss wire brush for $180 on a whim. That brush chewed through the whole thing in about 20 minutes and the homeowner tipped me $50, so it basically covered itself right there. What's the one tool you bought that felt like too much money until it got you out of a jam?