I have taken a slightly different approach. I did not wish to 'take any chances' and I personally have found no reason to 'trust' my insurance company. The relationship any of us has with an insurer is STRICTLY business and it pays to treat it as such and take care of business.
As such, at the advice of my agent, I specifically purchased additional insurance for 'defined' house valuables. In my particular case, it is 'fine arts' coverage. This is completely above and beyond our homeowners policy, and of course, it costs extra but is reasonably priced.
I then provide a 'very detailed' documented listing of exactly what is being covered. I choose, and document, either with bluebook values or apprisals, the value of the equipment (serial numbers, etc.) for which an item can reasonably be replaced in todays marketplace. I submit it to my agent, who then submits it to the underwriter. The underwriter is, of course, free (based upon their evaluation metrics) to either choose to cover or to deny coverage. Once the underwriter has accepted my documentation of contents, the deal is done. I am advised that in these types of situations (in the event of a claim) that a claims adjuster will very very seldom choose to take any form of exception with the choices of the underwriter, and even then that the only issue would be if there were reason to suspect fraudulent claims of ownerhsip. The underwriter has, after all, accepted binding documentation into a legal contract.
I advise my agent of any changes, and make sure that he always has a complete and detailed current inventory. I include all media within the coverage as well, and I admit that it can be a bit of work to detail and value this, but there is pretty good software available to make it easier. I email my agent a *.pdf of the documentation, and get a receipt of delivery. It makes a very nice paper trail.