also http://youmightnotnotneedjquery.com/

That site was not convincing. Why do in 8+ lines what I can do in 1 with jQuery?

Especially when the 8-line version might need testing in every possible browser out there for quirks and bugs. jQuery's already done the legwork there

Edit:

youmightnotnotneedjquery.com linked in a sibling of this comment explains it better in this googledoc

https://docs.google.com/document/d/1LPaPA30bLUB_publLIMF0Rlh...

When performance matters, or you are doing things on an order of magnitude, you may want to skip jquery

Do you have any examples or writeups to hand where rewriting jQuery functions ended up in a faster site?

Specifically in cases where other optimizations (caching, beefier servers, faster SQL, SSDs vs HDDs, etc) didn't help more?

Beefing up the server cannot improve client side code. Jquery is quite slow, nice, but quite slow. Sometimes writing out those 8 lines can make your code literally 400 times faster.(source : http://vanilla-js.com/) So yes if performance is a concern, you might want to look at writing it yourself.

Very good point, I'd not really considered the lower end spec'd machines, was more thinking overall page load times and the likes. Thanks :)

So if I buy a beefier server, my users with a netbook (ca. 2007) will feel a responsive[1] website?

[1] Responsive as in "Mozilla Firefox is not responding", not as in "Responsive Design".

Good point, not well made. Thanks for the response.

If anything, the examples it gives are persuasive arguments for jQuery.