3 strikes and you're out.

I'm nearly 50 and an extrovert and I've found that healthy and fulfilling relations are a function of reciprocity.

I'm willing to engage with someone 3x and see if they'll reciprocate. If not, I move on--no hard feelings, just realizing it's not a mutual fit.

This rule has served me immensely well in my friends. As a result, I have nearly no loose friends--just very tight, reliable connections.