DAE remember when we cut hair without checking the client's neck first?
I got tired of finding stray patches after a fade in my chair, so now I swipe my fingers along the hairline before I even pick up the clippers. I started doing it 8 months ago after a guy in Austin tipped me $45 and said his last cut had a bald spot behind his ear, and I've caught at least 5 near misses since.
The old "surprise" bald spot is a classic. Nothing like a client running their hand through their hair and giving you that look like you did it on purpose. I swear those spots hide until the mirror comes out, then boom, there it is in all its glory. Checking first just saves you the awkward apology and the free touch up later.