Boots suit anyone who walks more than they'd like to admit, whose feet get cold the second the clocks go back, and who wants one pair doing several jobs rather than three pairs doing one each. If you're someone who buys on a whim because a heel looked lovely in a photo and then remembers you have to stand in a queue or walk a dog in them, it's worth slowing down here more than with most things you wear. A boot that's wrong is wrong all day, not just wrong for an hour at a party.
The bits worth checking before you buy aren't the obvious ones. Look at the sole, not just the upper, because a hard slippery sole on a wet pavement will have you holding onto railings like a woman twice your age, and that's not what anyone needs in February. Check where the zip sits and whether it's backed by a bit of leather or just the lining, because that's usually the first thing to go. Have a proper feel of the inside of the ankle too, since a seam in the wrong place will rub a hole in your tights within a week and you won't know why until you take the boot off and swear at it. If you've only got one pair and you're starting from nothing, go for something low heeled, ankle height, in brown or black leather, nothing too pointed and nothing too chunky, because that's the pair that goes under trousers, under a dress, with thick socks in January and bare ankles in a mild October, and doesn't ask anything of you in return. Once that one's sorted, the knee high ones and the heeled ones and the lace ups become fun rather than necessary, because you've already got the boot that does the heavy lifting. For outfits, think about what's already hanging up rather than anything new: a straight pair of jeans and a jumper, a plain midi skirt you've had for years, a shirt dress you wear with tights from October onward. None of that needs a special boot, it needs a reliable one.
The detail that makes a good pair a pleasure, more than the leather or the price, is the bit at the top of the zip where it either catches on your tights every single time or glides shut without you thinking about it. You only notice when it's right, standing in a doorway with one boot half on, not swearing, just getting on with your day.