Question

A colleague of mine always sets their jQuery variables to null, to effectively dispose them, once they’re finished with, e.g:

var bigThing = $(body);
// ...
// Do some stuff
// ...
bigThing = null;

Is that really necessary?

Answer 1

If you encapsulate your code into functions thats unnecessary as after the function finishes the local variables will be killed anyway when no reference of them is used elsewhere.

Holding onto a selector/variable (caching) might have some positive effect tho if you need to select the same thing over and over again versus selecting it only once and keeping the variable.