Also, buy yourself a couple of external hard drives or even in fact just a pair of large usb drives to back up your important data.
+1. My friends' laptops seem to be very good at dying on them, even the ones who don't abuse them.
Absolutely. The problem's not so much with laptops (though they have additional failure modes compared to desktops such as being dropped, eaten by dogs, more easily stolen and misplaced power supplies) as with only having one computer, which is a bit like only having one bike in that it's sometimes necessary, but you need strategies for when it inevitably lets you down.
Can't give much in the way of relevant advice, as I hate laptops and haven't bought one since the early 2000s. Other than not to confuse memory (RAM) with storage (SSD/disk). Lack of RAM seems to be how computers become obsolete these days, so you ideally want something that's decently expandable, if not healthily over-specced. Storage is usually easier to upgrade, and even if it can't, you can offload some data and restore full functionality.
Oh, if you're even slightly fussy about keyboards or trackpads, try to fondle them before you buy. Same goes for screens, tbh. Beware of overly shiny ones, they're hard to read in daylight.
Ignore all the Windows vs Mac stuff that will inevitably appear on the thread. If
the three dead trolls in a baggie have taught us anything, it's that every OS sucks. Work out what applications software you want to run, then choose the OS according to that, like grown-ups do.