3. Will it Really Make Me Happier?
From a purely selfish perspective -- is this really going to make me happy? And for how long?
A lot of people enjoy experiences more than material things. If you're one of them -- going on a trip to see the Aurora Borealis would probably make you happier than buying a Rolex.
Me -- I'm one of those people who likes stuff more. But I've learned that giving gifts to my loved ones and people in need makes me even happier. It's long-term happiness too.
But if it's something that just feels good right now, but is ultimately meaningless -- I try to stay away.