My insurance agent asked me to make a list and take pictures of special items like collectibles, rare or expensive items like the longarm, featherweight 222 etc, and even supplies and fabrics, electronics etc.- including approx valuations - that I wanted extra or specific coverage for. Makes it much easier to replace if necessary.
Remember that replacement values are market values for the most part, and most things -like fabrics- depreciate with age. He asked that this be done throughout the house....not just in my sewing room. He also asked for updates to this list if any changes occur - like sales of machines or using up supplies, etc.
He suggested going thru each room with the phone taking a video of everything, making it faster and easier to file a claim if you need to.
This isn't really necessary to get the coverage, but it sure can avoid a lot of headaches later