Potentiometer selection

[DuncanK at kochind.com]

Okay, I've got schematics for various building-block circuits, both for
synth modules and for general audio.  How can I tell when to use audio
taper, and when to use linear taper potentiometers?

I presume something like a balance pot:

Left -----^v^v^v^v-----Right

With the signal pulled from the wiper, would be linear.  I also presume
standard faders would use audio taper pots.  However, when faced with
gain/cut and freq sweep pots (ala sweep eq's and such) I have no clue.
I realize the answer in each of these examples is, it depends...

But my real question is:
Is there something I should look for in a schematic, particularly in the
way a given pot is used, which I can use to guess whether to use linear
or audio taper pots?