Here's some info from Stratics - UO Stratics - Item Insurance

Basically, you can opt to pay 600gp per item to insure your armor and weapons (as long as they aren't cursed). Additionally, you can set your insurance to auto-renew upon death by toggling the auto-renew option. You can access both options from your character's menu - either single-left-click on yourself in 2D or shift-right-click on yourself in KR to bring up the menu.

When you die, any insured items will be waiting for you in your backpack upon resurrection. If you have auto-renew turned on, when you rez, you will also see 600gp (I think it's less if you died in PvP battle) withdrawn from your bank account for each insured item, as the game auto-renews your insurance.

Dying frequently can get expensive, but depending what you're wearing, it may be less expensive than replacing your armor and weapons.