Spent 3 hours laying out a wall last Tuesday before I figured out I was reading my level wrong
I was on a job in Akron doing a small garden wall and kept fighting it. Every course I laid, the bubble looked fine on my 4 foot level, but over 12 feet it drifted about a half inch out of plumb. I blamed the blocks, then the mortar, then the heat. Around the 3 hour mark an old guy named Sal from the next crew walked over and asked if I ever checked if my level was reading true. Sure enough, flipped it end for end and the bubble leaned the other way. The thing was off by enough to throw every course I set all day. Now the very first thing I do is flip the level and check it against itself. How often do you guys actually verify your levels, or do you just trust them out of the box?