Glendale, if you need a checklist to ensure you switch on the second mag after starting a Cub, may I respectfully suggest Golf instead?
Or use a checklist that starts "Item 1: Sit down".
Seriously, a very able but aging pilot I know of hung up his headset when he realised he'd flown a full hour in the Tiger Moth on only one mag. He reasoned, wisely in my view, that if his brain had addled enough for him to do that after many decades of not doing that, it was time to stop before something worse happened.
A good reason not to use checklists in simple single crew ops (other than ab initio when they can substitute for a level of knowledge not yet gained) is that they can mask 'not thinking'. And 'not thinking' while operating an aeroplane can be seriously life-threatening.