Just to represent the other end of the spectrum: me (43 years old, been hacking since I learned C64 assembly at age 10), who has 38 bookmarks and I don't think I've ever had more than 10 tabs open in my entire life.
You must have remarkable discipline and focus! Or you must have discovered the 38 exceedingly better sites on the whole Internet, and now no other URLs will do.
I always wonder why people have all these bookmarks. I think the most I had at one time was 15 and that because I switch to another project halfway. As soon I extract what I want in one page, I close it. If it's something that is interesting, and I don't have time, I add it to my read-it-later list. And if it's something that I may often revisit, that's when I bookmark.
For me the history in my address bar is the most important thing. Switching to a new laptop recently and not bringing those across, I became painfully aware how much I use this. Often the reference page I care about, or a deep link into some tool is a few keystrokes (the first few letters of the service and deeper link).
Bookmarks makes this info portable. It's like having close to O(1) access to the knowledge or tasks that are not immediately in your direct clickable range. Having extra non-title info makes this even better.
