This is why I prefaced with 'how you value your time'. I completely agree with you. If you're just after something that works, then just buy a new computer. If you like the project of injecting longevity, then the tradeoff is that you're getting entertainment out of your hours.

I'm very much a 'not dollars and cents' guy, but I see a lot of people struggle to maintain old computers when they're not really into enjoying that maintenance activity; those for whom an hour of troubleshooting -foo- is pure frustration with no fun mixed in.