Refrigerators should last between 7 to 10 years.
If your refrigerator is 10 years old or older you should be prepared to replace it with a new one soon.
I've never had a refrigerator last me longer than 10 years and I've had one refrigerator suddenly stop keeping cold after 7 years so the lifespan of the refrigerator can vary.
But what I do is put some money into a savings account to set aside to replace appliances so I have the money to just go out and buy a new refrigerator or other needed appliance.