Checklists seem to be one of those things sure to generate a discussion with much argy bargy between participants.
Learnt the following pre take off as a 14YO from a charter pilot who used to give a young boy a bit of stick time. It's about the only thing I can recite at the drop of a hat all these years later.
Hatches
Harness
Trim
Mixture
Pitch
Panel
Fuel
Flaps
Gills
Gyros
Switches
Controls
Lookout
A few things there seemed superfluous at the time, seeing as we were flying Tigers, Austers and Dragons. There was no such thing as retractable gear in GA at the time.
Can understand why "gear" might appear on a fixed gear type where the fleet consists of say 182, 182RG, 172, 172RG, 206, 210. Would be shameful at the end of a long and tiring day to forget that you're in a 210, and not the 206 you flew on the trip immediately after lunch.