Purchase price is the smallest number involved

What you pay to acquire something is rarely what it costs you to have it.

Every owned object has a running cost, even if it is only space and attention. Many have more than that: consumables that must be replaced on a schedule, parts that wear, power or water used in normal operation, cleaning that takes time, and accessories that turn out to be necessary rather than optional. None of this appears on the page beside the price, because the price is the number the seller controls and the rest happens after you are gone. Adding it up yourself is not difficult, and it changes the ranking of options more often than any specification does.

The method is simple enough to do on paper. List everything the item will need over a realistic period of ownership, including the things that must be bought separately to make it work at all, and how frequently each recurs. You do not need precise figures for this to be useful. Even rough relative amounts will show you where the real weight sits, and it frequently sits somewhere other than the purchase. Two options that look close at the counter can separate sharply once the consumables are in view, and the gap tends to widen with every year you keep the thing.

Then add the costs that are not money. Time spent maintaining, cleaning, or working around a design that irritates you. Space occupied in a home where space is scarce. The effort of eventually disposing of it or passing it on. These are real costs and people pay them daily without counting them. Counting them does not make you austere. It makes the comparison honest, and honest comparisons are what make a purchase easy to live with afterwards. The point is not to spend as little as possible. It is to know what you are actually agreeing to when you decide to own something.