My safe rules/philosophy:
- Everything else being equal, judge safe quality by weight.
- If bolting down, do so well away from edges. A Sawzall blade can easily slide between safe and floor, cutting through bolts like butter. The goal isn't to keep a thief from stealing your safe, but to prevent it from being easily tipped over. Prying the door open is far easier with the safe lying on its back.
- When installing on concrete, use a vapor barrier underneath to suppress rust
- If minor flooding is a concern (basements, garages, water heaters), you'll gain significant protection placing the safe on a 6-8" platform.
- Adding drywall to the interior will significantly improve the fire rating
- Don't skimp on humidity control - it's cheap insurance. I run two electric rods and keep a large box of desiccant inside as a backup.