The pros and cons of early retirement are pretty simple to figure out, to many peoples disappointment. I'm sure you'd prefer I said there were a lot of factors in this decision, which may make it so you can justify clocking out early, but the truth is that it's all pretty black and white when it comes to deciding when you can quit your career.
The pros of early retirement are pretty simple--you can stop working!
The negatives are a bit more complicated.
The first, of course, is your finances. Can you really afford it? This depends on a lot of factors. How do you plan on living? This will effect how much you decide you need to live on each year. Will you have paid off your mortgage by then? This will lower how much you'll need. Once you figure out how much you need a year, in today's money, you'll want to account for inflation and raise your estimate.
You'll also need to consider how many years you'll need income for to decide how much you'll need. Unless you have some kind of condition where you can make a better guess, you'll probably need to estimate that you'll live to be 95 years old, although it doesn't hurt to plan for 100. I know it seems ridiculous to save a great deal of money that you possibly won't be around to spend, but it's much worse to be 85 and broke. It's not like you'll want to pick up your career again at 85 years old, so, you need to budget for a longer life.
So, by these standards, if you can save enough money early to retire, then you can go ahead and quit your job and pursue whatever interests you.
There is something else to consider before you make such a leap, however, on a more personal level. What will you be doing with your time after you're free of your job? A lot of people quit their jobs excited about the time they'll have, and after a short while find themselves bored, depressed, and wondering what to do with themselves. I strongly suggest making a short list of things you've always wanted to do, whether it be volunteering, traveling, pursuing something like writing or horse back riding that you gave up in your youth. Make a list of all these things you'd like to do and keep in mind that you don't have to do them all at once, just keep them around so if you're over playing golf, or traveling Paris isn't what you'd hoped, you have other things to jump to do with yourself. This is your life, make sure you live it well.
With all of that in mind, the pros and cons of early retirement are pretty simple. The negatives can be taken care of by planning for your finances and making sure you know what you'll do with yourself, and the positives are that you'll have the time to pursue whatever interests you.