Proclaimers limit

The maximum workable distance for a long distance relationship. It is 1000 miles as specified in the Proclaimers song I'm Gonna Be which is the maximum distance one would walk to be with their lady.

Dude 1: I've been in a relationship with this girl but she's in New York and I'm in LA, it's really hard.
Dude 2: Yeah, that's a lot more than Proclaimers limit, that relationship might not work out, I'm sorry bro.
Dude 1: wha?

Dude 2: Proclaimers limit it's how far you'd walk to fall down at her door, it's 1000 miles...
Dude 1: oh man! I wish I knew, I guess it's time to move on...