I was very nearly 40 (40 is the age limit for the JET Programme, in which I participated, and I just barely squeaked through). I actually had to apply for the position a full year before selection, so it was something I thought about pretty thoroughly. (What follows is a bit of an autobiography -- sorry if it is boring, but I wonder if it might be helpful if you are going through some of the same things I did).

Dev experience is hard for me to measure :-) I worked at the university where I went to school. I also love to work and hate to study (err... "study" meaning attending classes or doing assigned homework -- for some reason I hate that and love independent study). So basically, I worked full time through school and squeaked through academically with a so-so mark ;-) Somewhat related, I even started a company at school with a few friends to write a game, but that got canned when the "business guy" embezzled all the money (great lesson, BTW).

Also, "sabbaticals" are not a stranger to me. In the late 90's I quit my job and spent 8 months writing free software. At that time I guess I had around 10 years of experience, depending on how you count. I had just suffered from working in a really messed up group and was questioning if I really wanted to be a programmer. Because I'm naturally frugal, I had saved up a fair amount of money by that point. My actual thought was, "I know I will need this money when I retire, but I think it will be better spent now." (In retrospect -- best thing I could have done).

To be honest, it was a crazy time. I would wake up at 6:00 am, go have a shower, have an idea while I was showering and literally run to my computer. Then I would program until it got dark. This is when I realised that I loved being a programmer and that I would do it as long as my body/brain could handle it. (Funny, but true story -- when I moved out of my apartment an older woman said, "Oh, are you the nice young gentleman who used to program in his front window all day? It's a pity you are leaving." Only then did I truly reflect that half the time I was programming, I was naked, having neglected to get dressed in my excitement to get back to the computer!)

At the same time I was doing this, I read a lot of daoist philosophy... Well... that's not really true. I spent a lot of time reading a little bit of daoist philosophy -- because it's incredibly dense (if you are interested, save time and just read translations with annotations by Richard Wilhelm -- He was German, but English translations of his translations exist. I wasted a lot of time reading extremely poor translations by people who didn't understand what they were translating). Later I wrote this: http://mikekchar.github.io/portfolio//UsefulAndBeneficial I still think it's the best thing I ever wrote (probably because I didn't really write it -- just pieced together other stories ;-) )

Armed with a better understanding of myself, I got another job and was very successful. After about 5 years, that job disappeared (the company was bought out and our division, being a kind of experimental division, was disbanded). I took the opportunity to take another 8 months "off". This time, it was less of a reactionary, "I need to find myself" affair and more of a deliberate, "I'm not going to get a job right away because I want to invest this time doing self study". Again, I wrote a lot of free software, but actually I was experimenting mostly with techniques around legacy software (refactoring, planning, prioritisation, etc).

I actually put all of my work on a business card sized CD-ROM and would occasionally hand it out to people who were interested in what I was doing. This actually landed my next job in a tiny start up. The founder had looked through my planning and prioritisation work and thought, "This is what we need!"

I really enjoyed working there, but the angel investor who bankrolled the company had similar qualities to the person who embezzled all the money in my game company. His interference cost the start up pretty badly and I saw the writing on the wall. After a few years I moved to another start up, but this time with an awesome management/investor team. I stayed there for a few years as well.

I was quite successful at this point. I had a good reputation in Ottawa, where I had mostly worked. I had a much bigger house than I needed. I had a good job, working with people that I liked. I had developed a way of working that was both successful and fulfilling for me. But... I've never been one to enjoy success, unfortunately. I always procrastinate because I hate finishing things. To accomplish something is to have it taken away from me -- I love to work on interesting problems.

So I moved to Japan. My initial idea was to go for 1 year to try to learn Japanese and to improve my mentoring skills. I had virtually no interest in Japan, and only picked it because: The JET Programme seemed like a comfortable way to do this kind of thing (and it is -- highly recommend it if you qualify: http://jetprogramme.org/en/), and also because I had randomly been practicing karate at the time.

After 3 months in Japan, I sold my house in Canada and incredibly reluctantly allowed my friend, who had been looking after my dogs, to adopt them (still sad about that, but also think it was the correct thing to do).

I think the most interesting discovery for me was: I don't have to be a professional programmer to be a programmer. In RMS's Free Software Manifesto, he spends considerable space devoted to the concept that not everybody needs to be a professional programmer. In the past I always read that section with considerable scepticism. But, at least for me, he was absolutely correct.

I loved teaching -- especially in a Japanese high school. I loved being with the students: chatting with them, helping them, joking with them, listening to them. It was at that point that I realised that jobs all have good and bad points and for a person who likes working (like me) there are probably hundreds of jobs that I will enjoy. Even though I love programming, I can do that whenever I want -- and on my own terms! That is the wisdom in the Free Software Manifesto. Whether or not you agree with the concept of software freedom -- as a programmer, you have a choice and you are free to take that choice. Do not overlook this!

I'd love to spout on more about that, but I'm sure I'm near the limit of the message size (not to mention your patience). I think Japan is still the best place to go to teach English comfortably. The other major place you can go is South Korea. I would say, try to find organisations that can place you in the school system (either public or private) because some of the "language schools" can be fly by night affairs. But it really depends on your tolerance for crappy situations -- some people are pretty good at rolling with the punches.

Also, even without leaving whichever country you are in, consider the idea of moving to the poorest, cheapest place that still has internet, renting an apartment for a year and doing whatever regular job you can find. You can probably do it for no more than $15K even if you don't get a job. When coming back to the industry, though, it helps a lot to be able to show what you've been doing during your sabbatical, so make sure to program every day :-)

Hope that helps!