The 5-10 rule for pocket pairs

Could somebody explain this rule, I seen it mentioned in a post about teaching a class for sit and go's.

Trevor

[AbelM]

I believe it's something like:

If it costs less than 5% of your stack limp with a low PP.
If it costs more than 10% fold your low PP.

In between that it depends on the nr of opponents, if they will pay you off etc.

[Newt_Buggs]

it really doesn't matter if you're an experienced player because then there is no need to bind yourself with rules.