On the first working day after the New Year in January 2013, I pulled my manager into a meeting room and let him know I was quitting my job. Two weeks later, I was officially unemployed for the first time in 15 years. At the time, I wasn't sure what I was doing next. After three years, I'm pretty sure that it's safe to say that I've retired. (And let me just say up front that this post is about why, not how, as in "how did I afford to do this." Might do the how another day. Suffice it to say that I have the means to live my current lifestyle indefinitely. Edit: A year later - here is the how!)
The short answer to why is this: lack of motivation. I've never been one of those people who love their jobs. I didn't actively dislike it (for the most part), but neither did I particularly enjoy the job itself. Going to work was something I did primarily because it was necessary. Once my financial situation was such that it was no longer necessary, motivation to keep going fell off very quickly.
That's not to say that I didn't like anything about working in the IT industry. I traveled to many interesting places, all over the United States as well as internationally (Australia, New Zealand, India, Malaysia). I met a lot of folks that I still consider friends. I got to work with a lot of interesting computer hardware and software. I was exposed to all sorts of different environments and industries, ranging from e-commerce to warehouse logistics to laundromats to health care. All good things, at least in moderation. But they're also all peripheral to the actual job of IT systems integration, which at the end of the day is mostly about augmenting business operations with technology.
As I approached my 15th year in the industry, I found myself wondering why I continued to go into the office each day. I felt like I was rehashing the same problems, same issues, same meetings day after day. Even when something "new" happened, like bringing in a new software system or starting a new project, it was similar to things I'd done in the past. That's a natural result of spending so long in the same industry, of course, but for me it meant that I was just going through the motions. The same motions, over and over.
I didn't immediately decide that the answer was to stop working. I tried making changes at work a few times. There was an attempt to move into an "architect" role, focused more on high-level direction than daily implementation issues. Then I tried changing from systems integration development to a systems administration role. (For the non-IT folks, that's kind of like moving from working on a phone app to maintaining the phone itself.) But after a short period of adjustment, I was back to feeling unmotivated.
Some people get motivation not from what they actually do in their jobs, but from making progress up the power structure. That didn't work for me, in large part because I actively dislike managing people. In 2007, I actually left my consulting job in part because the company had been pushing me to take more of a management role. I didn't feel pushed in that direction at the job I took after that, but it was also pretty clear that there was no other advancement path.
I certainly could have set other goals for myself, rather than dropping out of the work force entirely. I considered changing to a completely different type of IT company, or a different industry altogether, or going back to consulting. But as I thought about my options, I realized that what I really wanted to do was the stuff that you find yourself describing as, "if I had more time, I'd do..."
So that's exactly what I did...gave myself that time. And for three years, I've had absolutely no complaints. I haven't really even made a significant dent in my gaming or reading backlog, to be honest, though that's not for lack of effort. I've done some volunteer work (though not a whole lot), and taken a few trips. I get to see a lot of sports and watch movies that I'd never have bothered with while I was working. I have yet to find myself with a day when I just can't find anything to do.
Not everyone is in a position to be able to retire, or would want to. But it was the right choice for me, and three years in, I'm very satisfied with the decision.