It's important to have a self-analysis with these questions that I'll give you below.
Everything has a reason to be, a way of that or this, and it is difficult to do something without knowing why and for what. At least for most that include me.
A person will buy makeup or shoes thinking than he needs it without really think without being aware of what he is doing.
When he got home he realizes that he already had the same thing, and yet he has bought other things, maybe he bought that because he saw it on offer and he just decided to buy what they were offering him. The question is, does that person need it? Will you be using what you purchased before it expires? He kept adding more clothes to his collection, maybe because he thinks he'd wear them someday, maybe he was so cute he couldn't resist, but when he gets home the same thing happens again, it's something he doesn't usually wear, he found a pretext and stored it until the day when comes but the unknown is, will that day come?
When will you be able to use those bright colours? When can you wear that evening dress? When will that happen?
1. Why did I buy this?
2. Why do I need it?
3. Is it really necessary?
Remember that for each person the needs are different, and you should not be influenced by others. You can adapt your questions according to your need.