I occasionally hear about people who change strings once a week or more.
That sounds really frequent to me. I barely ever change strings unless one of them breaks, and then I only change the one that broke. I'll easily go 6-12 months without changing strings, and back in the day I played at least 5-7 hours a week.
I use Blue Steel 9s if that matters.
I also tend to go through strings pretty slowly, I usually change a set anywhere from every 3-6 months and typically use D'Addario or GHS Boomers. My one buddy goes through some sets in a day or two since his sweat consistency is quite acidic, and for this purpose he uses Elixirs. I will say though when I had Blue Steels they did last a remarkably long time as well.