You wont get a definitive answer as there are too many variables.
But just to list a few
Pad Compound
Riding conditions
Riding type
Ground type e.g. gritty mud
The type of braking you do e.g dragging vs late hard braking
Amount of use within time frame
Bedding in correctly (arguable but I always bed mine in)
Disk design, Some are known to eat pads.
Pad quality.
I only ever use genuine hope pads and they last ages. I stupidly bought 4 sets of superstar once and they lasted minutes before the friction material fell of the backing plates.
I remember reading something about hard braking being better as it continually glazes over the top layer of the pad making harder and longer lasting vs dragging a brake which exposes new material causing it to wear down faster.
The type of riding will also affect the lifespan. I have some avid juicy 3 that came on my commuter and they are still on the same pads as the day i bought it about 6 years ago. I ride it 8 miles 5 days a week but only probably brake 3 or 4 times per journey.
Edit: I have also stopped bothering with sintered pads as the hope organics last so long