I disable it. It improves speed and avoids many things that I don't want (sometimes just annoyances of animations and commercials and keyboard overriding and other annoying stuff, sometimes malware; disabling scripts doesn't always remove all of these things, but it helps).
I also disable fonts; I like to specify my own fonts instead. I also disable favicons, since it is not a feature I use, and third-party cookies, and some other features.
Sometimes I disable CSS too, and sometimes this compensates for disabling JavaScripts. Sometimes I also use user scripts and user CSS.