In practice, I found that by the time I would return to them (often years later), I frequently lost the context and the page went offline. So now I will typically instead paste the URL into an organized series of text file notes on various subjects, sometimes including a short summary of what interested me, a quote, or both. Even if I don't add a short note, I find that the categorization is more specific in the text file than the bookmarks, which helps contextualize the webpage. I'll also often either save the page to my hard drive or save it in Zotero, choosing the latter if I think I might cite it in a paper in the future.
I haven't stopped using bookmarks, but the bookmarks I have now are more ephemeral. I still sometimes fall into my old habits and use some bookmark folders for non-ephemeral things, but I've been getting better about this over the years. If it's in my bookmarks, it's probably not as important as what's in my text files.
A few years back, I did make a concerted effort to transfer as many of my bookmarks to text files as possible as well. I probably deleted over half of them in this process.
According to grep, I have approximately 43,957 URLs saved in my text files...