For those in the brain injured crew, the “reminders” app is an invaluable external memory device. On most smartphones, it’s present. The ubiquity makes me feel less like a freak (seeing as everyone has memory problems [some more extreme than others]).
So, to record plans, I use the “reminders” app on my iPhone. Whenever a new plans is made, I organise and note down everything. Ie date, location, activity, company, any other relevant details.
Everyday, especially for plants ages away, it helps me plan. Not just this, it allows me to prioritise plants. Allowing me to know what deserves my full attention, and full enjoyment.