OP here: I'm a back-end dev working on an internal company site. I have used jQuery for the past years for things like simple AJAX and manipulationg dropdowns. Recently I had to build an AJAX heavy part of the page, and got a bit lost in callbacks and DOM manipulations (1500+ lines already). There is no real reason to re-code everything, now it's working, but after seeing all the new shiny frameworks, I started to question my ability to maintain the code of this specific page ("Wouldn't this framework be better and easier to read/debug/extend?"). Still, don't know if one javascript-heavy page is enough to bring a new framework in the project and start over again.