Why does the same string always break when I tune/play my guitar?

The G (4th) string of my guitar tends to break much more than the other strings of my guitar (I think this is the 4th time in a couple of months). Sometimes it happens while I’m tuning the guitar, and other times when I’m playing it. I’ve looked at ‘how to string a guitar’ guides online and I still can’t figure out what I’m doing wrong. Is there some common mistake people make? Thanks!