Essential performance best practices for jQuery

I was under the impression that jQuery cached selectors, so the advice "Cache jQuery Objects", while smart for many reasons, would not actually affect performance much at all.<p>Was I wrong?

So is it generally agreed that $(window).load() should be used over $(document).ready() in most cases?

Oldie but goodie. Point #7, "Leverage Event Delegation", was particularly helpful for me.

A lot of this is outdated.