What do we want?
What is needed?
More important may be to ask, "What will make for happiness?"
When an object of desire tempted I used to try to define whether the item was a "want" or a "need". If it was simply a want I'd usually walk on. If a need, I'd make the purchase and be grateful I'd found it.
If it were both a need and a want I'd feel that I'd hit the jackpot! But there was something missing in this simple need vs. want formula.
Recently, I discovered what the missing factor was. It was "happiness".
Will it (whatever it is) make me happy?
What I've discovered is that there is a difference between the"novelty" of a new acquisition and happiness.
Novelty is a temporary enchantment that soon fades upon acquisition.
Happiness is much longer lasting, giving joy, contentment, and satisfaction now and into the future.
I've also found that many wants, particularly if they're objects, don't pass the happiness test.
Adding the happiness quotient to my formula has made much clearer what should come home with me and what shouldn't.