After 20 odd years as a programmer, I quit my job with the intention of spending 1 year teaching English in Japan. My main reason for doing it was that I wanted to learn Japanese and I felt that there weren't enough hours in the day to do it in Canada. I'm very risk averse, so I wanted to make sure that I had a job and a place to live. I was accepted into the JET Programme (I was 39 at the time -- the cut off age!). At the time, I had all the trappings of a successful developer: car, house, mountains of things in the house. I packed a backpack and let some friends live in my house rent free so that there was someone to look after it.
After 3 months in Japan, I knew I never wanted to go back to Canada. Eventually, I asked one of my friends to sell my house (that's one hell of a favour!) and got them to give away all my worldly possessions. I loved teaching English, although I was completely unqualified for it and it took me a few years before I was at all competent. My job was only 35 hours a week so I had lots of time to write code in my spare time and I did so almost every day. I learned Japanese fluently and even got married to a Japanese woman who didn't speak much English at the time. I stayed there for the entire 5 years that was available on my teaching contract.
After that, my wife wanted to go somewhere so that she could learn English. I was feeling quite a bit more confident at this point that the moving thing would work out... somehow, but I'm still very risk averse ;-) I managed to get an entry permit for myself and my wife through my English ancestry which allowed us to work in the country and we just went. We budgeted $30K for a year and in the case that I couldn't find a programming job I had a startup plan. I didn't have to worry as I found a job within a month.
Before we left, I warned my wife that it might turn out like it did when I went to Japan: that we would live in England for ever. We went with that view in mind and gave away/sold the things we had in Japan (except for a few things which we left at her mother's house). I, especially, was down to again owning nothing that I couldn't carry by myself. We stayed for 2 years (to the day!), but eventually decided to return to Japan to help look after my wife's mother who is getting older. I am now working remotely on contract for the same company that I was working for in London. We are very happy in Japan and don't plan to move again, but who knows.
For advice: You probably don't need to be as risk averse as me. Things will probably "just work out... somehow". I really, really liked staying in the 2 places for years on end. I have to say that I don't like travelling, per se, but I have really enjoyed living and becoming part of a community in another place in the world. Also, spending the time to learn Japanese and to learn a new trade has completely changed my life for the better. And I got married (which is actually a bit of a miracle to be honest).
In the 5 years that I was away from a programming job, things changed in the industry quite a bit. Also, getting a programming job in a new part of the world meant that I didn't have any contacts and the popular technology was quite different. Even though I programmed every day on my own, my technical level dropped by a fair bit. I had one especially bad job interview where I am sure I looked like a complete idiot because I couldn't do anything. But I ended up with a great job, probably precisely because I found someone who was willing to give me a chance to prove myself.
One of the responses here says to "plan to return". As you can see, I went the other way. I planned not to return. Either way can be good, but I agree whole heartedly that you need a plan because it can be an emotional roller coaster ride. If you plan to return, realize that your friends will have moved on in their lives, your job probably won't be there waiting for you, and you will fundamentally change. It will be like another new place.
Other people seem to be saying similar things about the things you have accumulated over time. You don't need/want it. Except for a few things that have incredible sentimental value, get rid of it all. Trust me. Having to get rid of your stuff while you are thousands of miles away is not a thing that you want to experience. Get rid of it before you go. If you can't easily carry it, then it is useless.
One strange, but I think important piece of advice: don't break local laws. I have been really, really careful, but I have met people who have had problems with the law in Japan. Things don't work abroad the way they work where you live. Even minor things that would be overlooked where you live now could be a HUGE hassle for you in a different country.
A big one for that is if you intend to get a job in the country you are visiting, get the proper visa. Many times you can get away without the visa and it will be fine. The times where you don't get away with it? It will not be fine at all -- especially if you like travelling. Spending weeks, perhaps months in a holding cell (which you have to pay a large fee for) until they deport you, and then having a huge problem ever travelling anywhere again... This is really not good.
I have a few friends now who work remotely for overseas companies while they travel. This can work really well if you plan things well (don't assume you will have good internet access/power!!!) Remote working is quite difficult, but also rewarding. That is a whole topic to itself.
My last piece of advice is to get comfortable with the idea that you will change on your trip. Circumstances will force you to be a different person. This has worked out really well for me and for many other people I know, but it can be shattering for some people. The "success" of the trip will depend more on how flexible you can be rather than how much you have prepared in advance.