I actually know a little about this topic so thought I'd post some points to ponder. Coverages vary with company and country, so it is imperative you check with your provider to get accurate answers, but here are some things to think and ask about:
1) Your gear might be covered under personal property as part of a regular Homowner's, Renter's or Condominium Unit Owner's insurance policy. Most of these policies limit coverage to personal equipment and usually exclude business property, so may not be adequate for a professional photographer for example. The broadest of these policies will extend certain coverages like theft to anywhere in the world, where others may limit certain (or all) coverages to within your country, state or even to the insured premises itself. Some may have specific limits for certain classes of property, so be sure to ask specifically about photographic gear. These policies usually are "Blanket Coverage" meaning you are covered for up to the total amount as stated on the policy, aside from the special limits referred to above. Settlement can be made at "Replacement Value" or "Actual Cash Value." Replacement Value means the item is replaced with the same item or if not possible, one of like kind and quality. Actual Cash Value is an acronym for "depreciated value," basically whatever the item's used market value is or worse, some value established by application of a company's standard depreciation table. Finally, this type of policy usually covers property on a "Named Perils" basis, which means only the named events stated in the contract will be covered. Invariably these will cover most common looses to your gear like theft or fire, but rarely will cover accidental damage or mechanical breakdown. Making claims on these policies generally trigger underwriting reviews and companies track both claim "Frequency" and "Severity" -- and too much of either can trigger a rate increase or worse, a non-renewal of the policy. So make sure you understand exactly how your coverage will work in case of a loss, ASK THE QUESTIONS BEFOREHAND!
2) Your gear might be covered as part of a Business Insurance Policy. The coverages and pitfalls follow almost identically above, though since this is a business policy, property is assumed to be used for business purposes. Just make sure you ask all of the above questions as it is far more common for example for a dedicated business policy to limit coverage only to the business premises and not extend it beyond.
3) Inland Marine. AKA, Floater Policy, Personal Articles Policy, Business Equipment Policy, and probably several other catchy names. Bottom line is this type of policy is a scheduled items policy meaning each item intended to be insured is listed at a stated value at policy inception, as opposed to the blanket coverage nature for the above examples. Next, it usually is broader coverage than above, meaning things like accidental direct physical loss are covered --- IOW if you drop it and break it, it should be covered. (Make sure you ASK what perils are and aren't covered by your carrier.) For this policy you list each individual item you want insured for a specific value and thusly maintain a "schedule" of covered property. For example you might have 25 items total listed, and let's assume item #10 is a $1000 lens. If you drop item #10 you can make a claim, and the company generally will pay you $1000 OR the actual cost to replace the lens, WHICHEVER IS LESS. Thus it is imperative -- and incumbent upon you as the policyholder -- to maintain the schedule accurately as far as items listed and amounts they are listed for. This means a call to your carrier every time you buy or sell an item, or prices on your specific items change. If you buy an item and don't call to add it, it isn't going to be covered when you drop it 3 months later. If an item's value increases and you don't call to increase the stated value, it's going to be under-valued at the time of loss. Companies will generally have separate rates for personal and professional (business) uses of the equipment, and offer deductibles from zero or full coverage on up.
Hope that summary helps,
. You have to decide whether you want to contribute to those risks or take a chance. It's good to add up what you DIDN'T pay for insurance in some little side corner.