I take very long walks, and often have ideas strike me as I go. Sometimes I want to remind myself of something I should do - sometimes I have the germ of a thought that I would like to flesh out in writing later - but I need to notate them or I WILL forget. Right now I voice text myself a brief message, and write it down when I get home. I would love to hear how other people manage this - I’m sure there must be a better way!