I think mine go about every other front tire change.
To be honest I'm not really sure how long mine last I just check them every time I change a tire and if they are starting to look worn out I change them.

 

I go through tires way more often than pads

 

Granted I probably change mine more than I need to but I would rather change them early than late.

There are several limits I push on my bike but brake pads aren't one of them!!

I've had a bad experience from not changing my brake pads soon enough and I won't do that again.

 

I just noticed that my RGU will need them soon, I have 15,000 miles, although I bought it used with 12,000.. My Roda King had 15,000 and looked to only be half worn... Both have/had factory pads.