I finally started using a torque stripe pen after a wheel came back loose

Last Tuesday I signed off a main gear tire change on a 172 and the next morning the line guy found two lug nuts backed off about a quarter turn. Nothing bad happened, but my stomach dropped when I walked out to the ramp and saw it. I had always figured torque seal was for the big jet guys and a guy with a good wrench and a decent memory didn't need it. Now I keep a yellow paint pen in my shirt pocket and stripe every nut I touch, and I check the stripe again before the plane leaves. Cost me $4 at the supply house and about 10 extra seconds per wheel. Anybody got a stripe color system they actually stick to, or is yellow just yellow and that's the end of it?