There is no real reason to buy a New Laptop these days and to me, many people buy new just to get the latest OS from Microsoft or Apple. They claim "slowdown" is the issue for buying new, but mostly it is cruft those Operating Systems builds up over time.
With Linux or a BSD, you will see how a real OS is suppose to run.
If you do buy new, make sure it is user upgradeable. For example, memory is not soldered onto the board, hard disk (HDD/SDD) can be replaced.