jenpax you can get a kitchen timer that hangs round your neck. Set it to 5 minutes if you're leaving a pan on the cooker. You can have the same pin for all your cards and, if your password is secure, you can use the same one for everything. You can make up a password from numbers and letters using a book.
For example:
1. turn down the corner of three different pages from 1 to 5. I used John Francombe's Deadly Finish for this example.
2. Use the page number e.g. 2 and the first 2 letters on that page e.g. ha (have), and do the same for the other pages e.g. 4 Ithi (I think) 5 Aquil (Aquiline). The password would be 2ha4Ithi5Aquil. Or you could use 245haIthiAquil. The turned down corners remind you which page, the page numbers tell you which letters. There's a mix of letters, capital and lower case, and numbers and that one is 15 characters. If you wanted different passwords for different sites, you could make a note on the flyleaf of each book. Keep the books handy. It would have to be a burglar reading this on GN to work it out, starting with who you are, where you live and which book!
If you use a smart phone you can set a reminder using the clock or calendar apps to remind you with an audible alarm when you have an appointment. You can choose how far in advance you want the warning e.g. the day before, an hour before etc. Just make sure you keep the phone handy!