Not trying to start any flame here just some hints:
Before just thinking that items are covered by your car and homeowners insurance please read the fine print or call your agent.
Most policies have a maximum and what is covered. Hobbies are typically not covered- ie boat in your garage isnot covered by homeowners.
Amount of property be it guns, jewelry, etc. Make a list and I suggest video taping and securing that list and video in a safety deposit box in case of fire- god forbide..
I like the idea of extra insurance-especially like today when I was using a rental car during race travel.