The lowdown on pads is that for a start there are only 3 manufacturers of pads worldwide, one being Shimano, the other two being taiwanese companies, one of which superstar use.
The wrond formula of glue was used about 4 yrs back and where possible they were recalled, but not all had batch numbers on so all the companies affected did the good thing and offered free replacements.
Winter wet weather kills all pads if they get rusty which is only to be expected.
If you want your pads to last there is one simple rule to follow and a couple of things that you can do to make them last longer.
Firstly never put a new set in in mid winter on a cold wet ride and expect them to last, they wont.
If you want them to last get them glowing (alpine descents) in the summer and then swap them for another set and repeat. The heat generated causes them to bond and harden, so do this to stock up pads for winter use and they will last longer.
Alternatively, bake them in the oven before use!
It all boils down to the heat they are initially baked at, cheaper ones get less heat for less time, fibrax being the worst culprit for being tight.
Lastly, always carry a spare set as you never know when you need them!
Hope that helps