How to know that the domain that you found is worth anything?!

[nupur_a]

Anyone can find any domain right, say I myself found a domain yesterday which is 'postchristmaslottery.com'. But how should I know that the domain I discovered is actually worth something in the real world or so? I bet you guys don't just go around buying domains in whichever you guys lays eyes into too, right? You verify the domain whether the domain is worth something or not?!

Which is the simplest way to do that?