My most used piece of kit is a gear bag with spare cold weather garments, a couple of old towels, Warehouse shower proof over trousers/jacket and some woolen hats. The number of times family and friends have dived into that bag to borrow some warm gear is amazing.
Hope I never have to use the likes of the trauma first aid kit or fire extinguisher [although have put out two vehicle fires over the years, neither of which were mine].
I also leave the PLB in the truck glove box when not hunting. Always know where it is that way and you never know when you might be on a country road and come across an accident and need to call in help without cell coverage.
Another good thing to practice ahead of time is how to get a GPS position off our phone that you can relay to emergency services. Again, if you come across an accident a GPS location will get services to the location way quicker than a verbal description of "three mail boxes up the second road on the left after the blue shed, next to a red shed, across the paddock from the pond".