How do you guys know when to push?

[skierdude1000]

I see people making lots of references to how profitable it is to push when sngs are down to 4-5 people. What do you use to make such decisions? I mean, personally, I push only when I'm first in the pot. I usually push K8+, 55+, A7+ (approximation). How do you guys know when to push or when not to push when you are multitabling sngs?