Treat kitchen rules like a secret handshake and you'll get free stuff everywhere.

Read some study once that people waste like 9 hours a year looking for stuff that's already in their hand or pocket.

Had a 2014 F-250 with the 6.7 that started making a funny tick around 180k miles. Did the paper towel thing in the shop parking lot and the oil had that dark gritty look with a gas smell to it, told me right away something was up with the injectors. Sent a sample in anyway because it was still under an extended warranty, and sure enough the report backed up what my nose already knew. That $30 kit just confirmed what a $0 check told me three days earlier. For the daily stuff I just pull the stick, wipe it, look at it in the sun, and rub it between my fingers. You learn more from that than any chart if you do it regular enough.