There are myriad ways to pull this off but more than a few them require luck of some kind. A particular technology, a particular company even a particular mana

There are myriad ways to pull this off but more than a few them require luck of some kind. A particular technology, a particular company even a particular manager. However a recent study shows that, in the US at least, 55% of all workers are laid off before they reach their "natural retirement age". So you need to plan ahead. Over the past twenty years the demand for technical talent has changed a lot. In particular, the demand has increased a lot at small and medium sized companies due to their use of the internet. So a useful outline of a career now is, start at a large company and learn the ropes, then move away from niche technologies to more generally in demand technologies like LAMP for example. By the time you hit 35 years old you should be starting to angle for more senior jobs at smaller companies. Software development now for smaller firms is starting to look more like law and accounting practices. Your experience there is now an advantage since you will understand more of the complete corporate needs in addtion to your tech chops. Whereas if you stay and a larger company (cough IBM) you're now just too expensive for you niche skill set. (*source - still doing lamp stack dev at over 60)