Upgrading to a higher efficiency model could cost less.
Well, first of all, consider what the man now has for his money: He had spent some $450 to replace a compressor. However, its operation is only warranted for a few months. What's more, the problem that originally caused the first compressor failure is likely still there. So, what is the system's life expectancy? Since the average life of residential HVAC systems is in the 15-year range, I would say that it was already five years older than it should be.