Someone I know said tires have a limited safe life span. I heard four years.
I bought a set of used tires fro my son's Hyundai Sonata. I did not check the production date imprinted on them. it's an oval with 4 digits showing week and year. I.e. 2508 = 25th week of 2008 or summer 2008. I just looked at them when I swapped from the winter tires. They are 10 years old! I've seen some minor cracking in the sidewalls. They do hold air, are nicely balanced and have good tread except for one of them. Of course the grip is now reduced but still good to very good. You rarely ever go to the limit anyway. I am sure winter performance would suck, but we have dedicated wither tires anyway.
In my opinion they are due, so I am looking for a good deal. Is it urgent ? No. Not for our way of using the car. It's a judgement call.
What happens in year 4? If you have a tire with a 90000 mile warranty and the average yearly mileage in the US is about 12000 shouldn't you get 7 to 8 years out of them?
In my opinion the 4 year limit is arbitrary and probably put out there by someone who has an interest in selling more tires.
Scotty Kilmer made a video referring to tires: https://youtu.be/6PM3M6lWGHM