Yesterday, I posted a couple of reasons that may justify quitting your PhD.
Personally, if I could go back in time, I probably wouldn't do a PhD again, simply because I don't want to be a researcher, but I'm still glad I finished.
But of course, there are also reasons to NOT quit even if carrying on may be hard at times. Here are 4 that come to mind:
It feels great to finish a big project. Admittedly, I didn't see that coming for most of my PhD but writing it up and suddenly seeing how all I did in the past four years came together like pieces of a huge puzzle felt pretty good.
You learn so much in the process. One thing is becoming an expert in your topic. That's nice if you actually like your topic but even if you don't a PhD teaches you tons of "real-life-things": Managing projects and, more importantly, managing yourself, dealing with unforeseen situations, dealing with all kinds of people, and much more. You can learn that elsewhere for sure but why not use your PhD while you're at it.
You build an international network. Working for several years in an environment that is as interconnected as academia also means you have the opportunity to build a large international network.
The title can be a door-opener. This may sound superficial but even if you don't want to stay in science having a PhD shows employers outside academia that you have certain skills - most importantly that you are able to teach yourself complex stuff.