Approaching 100k: Service, dual HID failure, and other questions.

I have 3 questions and did not want to start multiple threads...Let me know if I am better off posting these questions elsewhere.

Anyway, I have a 2006 Prius approaching 100k miles on it. #1: Seeing as the car is 12 years old, what services should I have performed at the 100k mark outside of the standard? Is the dealer the best option for this?

I have also had both of my HID bulbs go out. One was replaced by the dealer right after (used) purchase, as the bulb went out only a few days after driving it off the lot. So one was original, the other was a recent replacement. The oldest one crapped out, and a few days after, the newest one started flickering and now is fully out. They both power on momentarily. #2 Is this just a coincidence or have I potentially damaged some other electrical component?

I had the HV battery fail summer 2016. I got a reduced price after seeking a goodwill warranty from Toyota, this was still a large financial burden, and I would like to avoid this for at least the next few years. #3 Are there steps I can take to ensure the battery lasts?
Surely heat can't be good for the battery and I am expecting another brutally hot summer here in the south so I try to park in the shade and use sun reflectors, but there's little one can do when its 103 degrees...

Any help or insight is much appreciated.