Before you buy any cabinet or sideboard, measure the depth of the doorway it has to travel through, not just the room you're putting it in. I have seen a beautiful piece get stuck in a stairwell and have to go back on the truck, and it is always the depth, never the width, that catches people out.
When it arrives, open every door and drawer before the delivery people leave. Run your hand along the inside edges where you can't see well, because that's where cheap finishing hides, rough particleboard under a nice veneer top, or a back panel stapled on instead of set into a groove. Push on the top corners and see if the whole thing racks or stays square. Drawers should glide without you having to lift the front, and doors should close with a soft, even click, not a slam because the hinge is already loose. Over months of actual use, the difference between a good one and a bad one shows up exactly where you'd expect: the hinges, the drawer runners, the surface where mugs and keys land every day. Solid wood and good veneers age well, they pick up a little warmth and a few honest marks, and you can touch up a scratch with oil or wax and it mostly disappears. Laminate doesn't age so much as it just starts failing, edges lifting at the corners first, usually near a steamy kitchen or a radiator. Keep anything with a wood finish out of direct sun unless you want one faded panel and three normal ones. Wipe spills quickly, and don't let a damp glass sit on an unsealed top overnight, that ring is forever.
The build tells you everything if you know where to look. Dovetail or dowel joints on drawers beat a drawer that's just glued and pinned together, every time. Doors that are a solid frame with a panel set inside will outlast a flat slab door that's really just a box. Metal runners with a soft close mechanism are worth paying for, because a cheap plastic runner will crack within a couple of years of normal use, maybe sooner if it's holding anything heavy, like files or glassware. Check the back of the piece too, a proper back panel screwed into a frame keeps the whole cabinet rigid, while a stapled hardboard back lets it twist over time, which is usually when the doors stop closing properly.
The one mistake worth avoiding is buying a piece that looks finished and ready off a screen without checking how it's actually held together, because the parts you can't see in a photo are the parts that decide whether this lasts five years or twenty.