Also there are differences in further employment perspectives. I mean if you have a problem to solve and you have a choice to use some old tech that you alread

Also there are differences in further employment perspectives. I mean if you have a problem to solve and you have a choice to use some old tech that you already know, but it is going out fashion, and some new one, then the choice of the newer one improves your employability in the future. For example, I guess in 2000 there was not that much people with 5 years of experience of using Java in production, but those who had it, had to have pretty good chances to easily find decent job. Of course there is a risk to bet on wrong technology, but at least you keep learning instead of just using ageing tools and becoming more and more disconnected from the current state of the art. It can be as scary as this https://news.ycombinator.com/item?id=11886753 https://news.ycombinator.com/item?id=11886753, a story of a guy who successfully solved business problems and delivered products with jQuery for a long time and then eventually found that he was out of demand because businesses started looking for people with experience of using React and he didn't have it.