When flying a basic light aircraft with no "modern" instrument the pilot needs to remember to do various checks on a regular basis (FREDA every x minutes, change fuel tank every Y minutes etc.).
Just flying the plane can be consuming a lot of attention (especially without auto-pilot or if you become unsure of your position) and it's easy to forget to run those checks. I wouldn't want to forget changing fuel tank so I was wondering:
What are the tools that I can use to make sure that all checks are done on time?