Despite new technology introduced every year and the best golf irons released each season looking very tempting to me, I have used the same set of Mizuno MP-5 blades since 2016.
These stunning 2015 chrome musclebacks are still some of the best looking irons I've seen and they're performing well for me a decade later. I can't really say how often you should upgrade your irons, but I would be happy to play these for another few seasons at least.
