I have a few thousand entries in a few journals.
My main encrypted personal lifelogging journal is broken down by year and I archive previous years’ journals - that is, I don’t sync them to iOS. I’ll often include a pic or two in an entry, but that’s about it. My personal journal usually has 1-3 separate entries per day.
I’ve never used the new audio feature. I used to pull in my tweets, but then was before I went on a social media diet and deleted all my tweets. I do like the option to tag where I am on a map for my entries. I used to use #tags but gave up on it and resort to search (which to be honest is pretty rudimentary and the most annoying thing about the app to me).
My other journal is a food/workout journal that gets updated throughout the day, one post a day.
I like Day One a lot and I use it a lot, but I’m not using browser extensions or making books or photo albums (on their podcast one of the employees has a journal consisting exclusively of photos of concert tickets). The Mac app doesn’t get as much move or feature parity as the iOS app (which makes sense, given the sales and use of the service/apps) which is a little frustrating since I use it as much on the Mac as on iOS and I’d at least like to be able to have the same font choices on both apps.
The site has a nice section detailing how users employ the app.
Ultimately, given my modest needs I could probably move to another app (even a non-journaling-specific app, like Notebooks) if I wanted but I’m fairly content with the current setup for now.