Let's put it this way: I've regretted going cheap on vacation, every single time! And *I* know better than to cheap out. But my husband continually thinks hotels/rentals are too expensive and if he makes the reservations, it's going to be to places that are dirty, or have inadequate hot water, or where something is somehow not right.
So for example, AirBnBs: I don't want to be stuck using one bathroom for our family. In many places in the world, you need to reserve a 12+ people rental to get two decent full baths, so that's what I do, even though we're 4 or sometimes 6. It also gets me "nicer" places, with decor and attention to detail, etc. Not a ramshackle mismatched place with kitchen things that don't work.
Hotels, same thing. I want comfort with nice cotton sheets and quality mattresses, light switch controlled from the bed, and well-designed bathroom fixtures, not the toilet paper 3 feet from the toilet. Healthy options at the breakfast buffet. I mean, are these BASIC things too much to ask?!?

Yet they sometimes don't occur automatically in moderately-priced hotel rooms, which is why I upgrade.