I’ll admit I only graduated high school back in June and I already forgot how to do long division. I do know trig and the unit circle and whatnot pretty well though, and could do 51*51 in my head in about a minute.
That said, I don’t remember much from precalc, and barely passed it. At my school we had to write a full academic paper in our senior year and that took a lot of my energy. I also wasn’t allowed to drop any of the electives I took even though I didn’t need the credits, which meant I struggled a lot towards the end of senior year and many of my classes suffered. Somehow I still got a good GPA.
I’ve adopted a policy of buying the latest iPhone every 5 years, which is about how long they tend to last in my experience. So far it’s worked out well.