I'll give you my example.
I have a simple cellphone and I want to buy a smartphone. But, I have 2 PCs. 1 laptop and 1 desktop. I don't use my desktop too much any more because it is on my parents house, and my laptop is a bit old now (Dell vostro 1520). So I need a new laptop and I'm thinking in sell my desktop. After that, I can seek for another laptop, then sell my old one. But, wait... I can buy a smartphone with that money.....mhmmm..... What should I do?
I'm choosing a new laptop. It will be more useful than the smartphone.