I just got in the habit when XHTML was looking like the Next Thing, I was actually using it in a lot of stuff, XHTML died, and I never stopped doing it that way because I always felt it was more consistent than having some tags be self-closing and some not. Funny enough, I had been doing things using Thymeleaf templating the last couple years, and it does the HTML template as XML, so you have to close all your tags. I think that has to be some kind of procrastination achievement.