When I was getting started in my career, an older coworker on mine in his late 40's shared with me some tricks of the trade, and he said to me "My calendar is what I live and die by, and if you're like me and can't remember shit, use your calendar on your phone".

To this day, any and every appointment to the most mundane tasks, goes in my phone. It's helped me stay more organized, and saved my ass more times than I can count in terms of reminding me about appointments I would've otherwise totally forgotten about.