Less is more.

For personal use, I fixed myself on HTML5, CSS Bootstrap and jQuery JavaScript. Sometimes I’m curious about other choices, but being a long time programmer (I began in business in early ’80) I can see quickly if it is worth the time spent getting used to some new approach, and usually the answer is negative.

I remark this is my option for personal (and for fun) projects. In professional work I’ve always learned the current framework, sometimes getting surprised and pleased by an unknown language or feature or working flux, and a few ones suggesting changes after observing the whole picture.