I spent years thinking a tote was just a bag shaped bag, the thing you grab when you can't be bothered with zips and straps, and I bought three cheap canvas ones in a row that all did the same disappointing thing: the bottom bowed out like a nappy within a fortnight because there was nothing holding the shape except hope. What fixed it was finally picking one up with a proper structured base and feeling the difference in about two seconds, before I'd even put anything in it.
The good ones have weight to the canvas or leather before you load them, not after, and the seams at the base are reinforced rather than just one line of stitching holding everything up under the weight of a laptop and a flask. Check the handles too, stitched through and anchored to the body of the bag, not glued on or riveted through a single thin strip that'll start pulling away the first time you sling it over a coat. A lined interior matters more than people selling totes tend to let on, because an unlined one collects pen marks, crumbs and the fluff off tissues at the bottom, and you'll be fishing around for your card past all of it. Hardware, if there is any, should feel like it belongs to the bag rather than looks tacked on as an afterthought to justify the price.
A tote clashes with anything else bulky on the same shoulder, which sounds obvious until you're wearing a big coat and trying to also balance a cross body bag and wondering why you look like you're moving house. It also doesn't do you any favours with very fitted, tailored outfits, the kind where the whole point is a clean line, because a soft slouchy tote undoes that in one go. Before buying, open it right up in the shop, check the base seams close up, tug gently on the handles, and look at how it sits empty. If it already looks a bit saggy and shapeless with nothing in it, that's exactly how it'll look after a few months with everything in it.
Mine's been through two winters now, thrown onto buses, used as an overnight bag more than once when I didn't want to admit I was packing light, and the shape's held because the base never gave in the first place. That's the whole test, really, not how it looks on day one but whether it still looks like a bag and not a sack three months on.