If by "upgrade" you mean actually pulling out an old card and replacing it with a higher spec card, then it's been a VERY long time. I usually get a high end card when I build a new system, and that generally stays together until I'm ready to upgrade everything.

I've currently got a RTX 3090, and haven't really been feeling any pressure to upgrade. I'll probably ride this one out for another few years if nothing majorly changes, before i build a whole new system with whatever high end components are available at that time.