What the logbooks have turned into is an index of my life. I consult them to reminisce about important events, like the days my kids were born, but I often consult them for really mundane stuff, like looking up the last time I replaced the air filter on the furnace.
That’s pretty much why I keep a log/journal too. Just today I was asked if I had attended a certain conference this summer. I wasn’t sure anymore since there were some trouble around booking and timing (which led to some confusion around if I even had a ticket for the event or not) and I knew I had attended a conference with a similar topic this summer. Turns out, I hadn’t attended that specific event. With the date of the conference it was just a minute to look up the days in my log and find out.