I've worked as an underwriter (Commercial Insurance not Personal / Home Insurance) for 34 years. I'm now an underwriting manager for a major UK insurance company, working in the City of London.
I post on a number of photographic forums and there's a thread about insurance on most. The extent of cover - and, consequently, the price you pay - will vary dependent upon:
1. Professional or Amateur?
2. Where is the kit kept when not in use / not with you?
3. Do you travel extensively overseas?
4. Claims history
5. Sum insured*
6. How is the property secured (a) in your home and (b) when you are away / overseas
*sum insured is an interesting one. Most insurers offer "reinstatement cover". This means that so long as your sum insured is adequate to replace your kit - AS NEW - then the insurer won't reduce the claim payout proportionately. If, however, you insure for £10k but your kit would cost £15k NEW, you would receive £6,666.66 (less any excess / deductible) as you'd only insured for 2/3rds the value NEW.
The "AS NEW" value also needs to reflect the fact that your kit may not still be in production. If we're talking about, for example, a Leica M6TTL, these are no longer made. Don't fall into the trap of thinking, "Oh, I could get one of these for £xxx" and insure for that amount. As the M7 is still being made, that would probably be the "AS NEW" replacement. Therefore, although you own an M6TTL, you would need to insure at a value capable to purchase an M7 with bradly the same functionality.
If you have kit that is no longer made and there is no "AS NEW" alternative, you should contact your insurer / broker and ask if they can arrange for an agreed value option whereby you insure for the cost of the same item as you own - but as if you were replacing it with one of the same age and condition.
Don't mess up with what is referred to "the basis of claims settlement" condition as that is where many claims come unstuck and it all comes back to getting professional advice - and I would always recommend using a broker / intermediary.
Also, consider the potential for you to cause injury or damage when taking photographs (Public Liability Insurance) or for professional negligence - i.e. photos don't turn out on a paid job or you screw up in some other way that costs money but doesn't cause injury or damage).
View the responses on these websites and then do what's right for YOU.
Finally, be completely honest and open with your insurer / broker. Hide no facts that might influence their decision on whether to provide you with cover. the company I work for has a very effective and efficient anti-fraud team. We hate increasing our honest policyholders' premiums as a result of the selfish actions of a few fraudsters.
Cheap insurance obtained fraudulently usually ends up very expensive when the insurance company refuses to pay your claim - and it makes it incredibly difficult for you to obtain insurance from another insurance company when you have to disclose that an insurer refused your claim and/or cancelled your previous policy.