It's true that it's generally a bad idea to trade for a new machine every year. The guys that do that either have to get a lot of hours on, or they burn an insane amount of cash. If you look at depreciation and repairs, the yearly cost of owning a machine doesn't level off until the machine is approximately 4 years old. This means that if you bought a 4 year old machine and kept it, your repairs should increase at about the same rate that your depreciation decreases. If you work with a machine that is less than 4 years old, you are getting the shaft when you try to trade it in. The example you just gave is perfect: A $150,000 machine is only worth $50,000 after three years. You're losing over $30,000 per year in the value of that machine, and you'll have to run that machine for years to reduce the depreciation cost to an acceptable level. This post is probably getting way off topic. Feel free to send me an email if you'd like to discuss it further.