We bought our fridge 25 years ago when we moved to this house.
About a year ago for the first time ever the fridge was just not cold. The freezer was.
I dug around online and found a common cause is the defrost heater. I pulled the food out of the freezer, and took off the back panel, and I decided it looks a bit frozen up.
Out came the heat gun, and I got it defrosted.
I found the problem. After 25 years the heater fried itself.
I ordered one online, and when it arrived a week later there was some frost to defrost, but not a ton. Swap in the new heater, and all is fine again.
I love that old fridge. The ice maker works great, and has no expensive filter to replace regularly. No internet connection of electronic touch screen panels, just a good reliable system. With new fridges at the cost of a decent used car, we will stick to the one that works.