If I don't get enough sleep, especially for several successive nights, I have trouble focusing, so I avoid making any important decisions when I'm mentally tired, if possible.
A couple of days ago, I had to take care of some business and was out of the house quite awhile. It was a physically tiring day, but mentally stimulating, and my thinking seemed clearer and motivation was up more than it is on days when I'm home with little to do.
I keep an online journal and at the end of each day I briefly record what happened that day. I've found it useful to look back at times when I may forget certain things that took place. Like, when was my air conditioner serviced? I can enter "air conditioner" in the text document word search and find any associated events, the date they occurred, and what took place.
It's been said that we shouldn't rely on notes, because we can become too dependent on them, but I've done that most of my life. While at the computer, if something comes to mind I need to do, I jot it down on a pad and that way I won't forget. It's a bit inconvenient, but I'd rather rely on notes than forget it.