Useless tips.
Your vacuum cleaner purchase is an example of how wrong you are. A vacuum cleaner is pretty much necessary. You will always own one and they haven't changed much. So why buy crap? You will end up buying a lot of crap vacuums which may end up costing more than the good one you didn't think you needed and will waste time buying replacements.
Your tip for buying cheap only applies if you are buying disposable items or items you will only need once.
Your Rolex reference is also foolish as the are much cheaper watches that will last a lifetime. I suppose it would be nice to have purchased when you are looking to pawn something but otherwise it is just trying to impress other superficial people.