Word usage tip: "farther" vs. "further"

Here's a classic word usage problem: farther vs. further.

You can hear and see these words getting mixed up frequently on television, radio, in print and in everyday speech. The rules are simple:

Farther is to be used  only for physical distances.
Further is to be used for any other extension of time or degree.

Pretty simple, right?

Here are two examples:

He went farther into the woods than I did.
He went further in his career than I did.

So, just keep in mind: Farther is for distances and further is for all other uses.