When do you change your strings?

I was reading this Article about changing strings before recording, and I was wondering what the membership here does (or doesn't) do.

When I was gigging, I'd have to change them about every second week because I sweat like a pig under the lights and the strings go dead very quickly!

Now, out here next to the ocean in the tropics, The tarnish and rust in a heartbeart - I should probably use some sort of protection on them -, and sliding your finger up a rusty string isn't as much fun as it sounds, so regular changes would be necessary if I was playing them on a regular basis. Which I'm not. To my shame.