Discounting Chip Value in Pot Odds Calling

[BPA234]

Here is a quick question that I need help on:

If the chips you win lose value after you win them, what % of discount should you use when evaluating a pot odds call?

Typical scenerio is you are in BB with average or better than average stack and your all-in opponent has a range that warrants a call at 2 to 1. But, if you discount the value of the chips than the pots odd reduce and a fold is the right play.

Any thoughts?