Have you seen the inside of your parking brake?

I'm going to use the pic as an example if that's ok. Having pads this worn could lead to caliper and caliper piston problems. Just make sure when you press your piston back in the piston boot is in good shape and collapses evenly without pinching it. Looks like the pad had an 'even' surface of wear though, so that's good. Just means the caliper pins and sliders are working and be sure to clean them up real good and put a little anti-seize on the pins again when you put it all together.
Of course you likely knew that, not trying to insult your intelligence!

As for pad life, it all comes down to driving habits and you should be checking your pad thickness every oil change or when you rotate your tires if you have a different schedule. Always be sure to check the inside pad carefully as it wears faster then the outside one.
Nice writeup about the parking brake issue though, even though I have an automatic and use my e-brake very few times. I'll be paying attention to how it reacts over the course of my warranty period.






