Not gonna lie that reasoning makes no sense to me, unless you have an actual problem with your current laptop I don't think "just in case my current laptop stops working" is much of a reason. Why not buy a new laptop when it actually runs out of life?
Also second hand laptops are awesome. Save money, save the environment and there is hardly any difference between a laptop today and a laptop from 2 years ago. You could even get a faster laptop with the money you saved from going second hand.
Anyway spend your money how you like, I have a bad habit of getting into an argument with everyone I talk to.