The most widely accepted guideline: if the repair costs more than 50% of what a new appliance costs, replace it. This accounts for the fact that an aging appliance will likely need more repairs soon.
Average Appliance Lifespans
Appliance
Average Lifespan
Replace If Older Than
Refrigerator
13-15 years
12 years
Washing Machine
10-13 years
8 years
Dryer
10-13 years
8 years
Dishwasher
9-12 years
7 years
Oven/Range (gas)
15-17 years
13 years
Oven/Range (electric)
13-15 years
11 years
Microwave
7-10 years
5 years
Always Repair If...
The appliance is under warranty (check manufacturer + retailer warranty)
It's a simple fix under $100 (door latch, filter, belt, fuse)
The appliance is less than 3 years old
It's a high-end appliance that would cost $2,000+ to replace
Always Replace If...
The compressor failed on a 10+ year old fridge ($800-1,500 repair)
The control board failed AND the appliance is 7+ years old
You've already repaired it 2+ times in the past year
Energy costs: a new Energy Star model could save $50-100/year in electricity