How's the rotor look where the pad was? If the rotor is scoured it will eat the new pad up also.
The calipers may be sticking and not "floating" like they should. Road debris, sand, salt, ect. can cause the calipers to drag at times. If the brakes had been replaced before then there's always the chance the rotor wasn't turned or that the rotor has become scoured up on that one side which ate the pad up over time. The rotors are thinner today then they used to be. Some of them are only able to be resurfaced once since there won't be enough thickness left for a second resurfacing down the road.
Some vehicles are known to "eat" brake pads up ([cough] Pontiac Grand Prix [cough]
) but the Tahoe isn't one of them that I know of.