How often do you replace your brake linings?

[whereisjim]

I did my 45k check-up around week before my warranty expires. Two days after warranty expires, 'Check brake lining' light came on.
Took back to the dealer and complained. They told me that they replaced both front and rear.

Now two years and 3 months later (drove around 25k), the light came back on.
Tried 'Open driver side door, leave key to '2' position and wait' trick but won't turn off.

Before I hit it back to the dealer, just like to ask folks that if this sounds right or not?

If I bring it to different garage, can they tell if the brake pad were replaced back in two years ago?

How often do you guys replace your break linings?

TIA.