That is a tough one. I have been in the industry for 10+ years and a lot of it in the higher end custom home side. To me a couple of things that standout as s

That is a tough one. I have been in the industry for 10+ years and a lot of it in the higher end custom home side. To me a couple of things that standout as super cheap are jump ducts (basically they didnt bother to put a return air duct in a room and just put a whole in a wall with grills on either side to allow air transfer), hollow core interior doors (you can hear/feel the difference if you knock on a hollow core door versus a solid door), all stucco exterior (cheapest clading material where I live), sometimes upper floor water pressure is almost non-existent and they dont put in a booster pump, and on and on... I feel like it really varies from project to project. I have seen some where they actually spent a decent amount on the cabinet drawer/door fronts, but then didnt bother to spend a couple of hundred more on good undermount drawer guides. Others where they didnt bother to think about layout/flow in a kitchen (aka the island looks great, but if I open my fridge I cant squeeze by the island and the door to actually get anything out of it). I think generally a lot of what people are trying to build today qualifies as "modern" but to me it just looks/feels cheap. To truly do modern well is very expensive. I dont particularly like the look, but thats just my opinion. Older construction is another area entirely. When flipping houses became popular a lot of people got into the industry who didnt know what they were doing, or they went about trying to do it as quick and cheaply as possible. I have heard that the less you know about a place you are trying to flip the better. AKA if I dont open up any walls to see if the electrical doesnt actually meet code, then I dont have to spend a bunch of money replacing it! Or I didnt get a structural engineer to look at the foundation so I dont know if there are any issues with it and therefore I dont need to disclose anything to a potential buyer.