The one thing to check before anything else: open the door and see how far it swings. Not just whether it clears the handle on the fridge or the drawer next to it, but whether it clears your own body when you're standing in front of it trying to actually get something out. I've seen plenty of units that look fine in a showroom and then turn into a daily shin bruise the second they land in a real kitchen or hallway with less breathing room than the floor plan promised.
Measuring for one of these is less about the cabinet itself and more about everything around it. Write down the width, height and depth of the actual opening you're filling, then add clearance for the door swing, plus a few extra inches if there's a wall, a radiator or another cabinet close by, because doors need somewhere to go that isn't straight into a wall corner. Depth catches people out more than width does, a unit that's deep enough to be useful can also eat a hallway or stick out past a kitchen island in a way that looks fine on paper and terrible in person. In the shop, run your hand along the hinge side and open and close it a few times, cheap hinges feel loose or catch slightly, good ones feel like they want to close themselves. Check the door sits flush when shut, not angled or gapping at one corner, that's a sign the cabinet itself is slightly off square, which you will notice every single day once it's in your house. And measure your doorways too, I learned that one the hard way when a unit that fit the room perfectly would not fit through the front door of the house, so it sat in the driveway for two days while Mike made jokes about turning it into a potting bench.
Where it goes matters as much as the size. A heavy, solid door cabinet can look wrong next to open shelving or a glass front piece, too much visual weight all on one side of a room, so I'd balance it with something lighter nearby rather than lining up two closed, chunky pieces together. It also struggles in a really small entryway or a narrow galley kitchen where every door swing is a negotiation. Where it earns its keep is anywhere you need storage that disappears, a mudroom, a living room holding board games and cables, a kitchen where you want the counters clear. It suits an older house with real walls and odd corners just as well as a new build, maybe better, since it hides the stuff that doesn't match the rest of the room. Before I buy, I always ask myself the same thing: if I opened this door fifty times a week, would I still like how it feels in my hand?
