I've covered this topic before. Here's Jacques Mattheij's take on it is that you should only drop out if you are running towards something (basically, your own startup that's taking off like a rocket ship and making a lot of money already), rather than away from something (you're bored, don't like it, etc):
So, if dropping out is an escape of sorts, don't do it. Stick to it, finish what you start. If your school or university is holding you back from achieving your full potential then drop out with confidence.
The simplest test of whether or not you should drop out is this one: If you have to ask someone if you should then you shouldn't.
I'll add one more reason not to drop out:
You shouldn't drop out just because "other people have dropped out and did great". The chances that you're the next Steve Jobs or Bill Gates are, well, 1 in 3 billion.
There are plenty of reasons that are directly related to you and are not good reasons to drop out (and some are outlined by Jacques). Definitely do not drop out based on the idea that since it worked for someone else, it will work for you. Most people will lose a lot by dropping out. I know a fair few very smart people who dropped out of university or simply didn't consider going, and all of them, without exception, regret it.
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