Justifying a New Bike

How to Justify Buying a New Bike -
Use the "cost per mile" method: cost/distance. Get a new one when the cost is below your target level.

If your bike costs $2,000, and you ride it 2,000miles the cost per mile is $1.00. Once you ride it for 4,000 miles, the cost is now $0.50 per mile. At 8,000 miles, the cost is $0.25. At 10,000 miles the cost is $0.02 per mile. At 20,000 miles, the cost is $0.01.

If you average 1,500 miles per year, that's 13 years, which is long enough for a bike, if you don't have any accidents. The difference in bike technology over 13 years is enormous.