Well it depends the nature of the project you're starting from scratch. If it's a new project at your employer, there could be factors like "how easy would be t

Well it depends the nature of the project you're starting from scratch. If it's a new project at your employer, there could be factors like "how easy would be to hire / train people to work on this project in the future?" or "how mature this technology is / how likely is it that unknown problems will bite us in the ass in a few months or years". But if it's for personal use, I guess it's a matter of what your main motivations are for it. Personally, if I'm building an MVP or in other words, my main reason for building it is to get it in front of customers ASAP, I probably go with the stack I'm most familiar with. But other times I start a project just to play around, learn or get more familiar with a new stack, so then I do just that.