The more panties you have the less concerned you have to be about getting them torn off.
[url]http://[/url] I'm a sock hoarder (which is ironic because I hate wearing socks) so I totally know where you're coming from. It's not too many unless you think it's too many (or you start selling your possessions to pay for new panties).
I couldn't possibly say how many pairs my girlfriend has (fewer than 85, I imagine). She's always bugging me to get new underwear because the elastic has gone in most pairs.
You go get your panties, girl!