Most homeowners have insurance on their homes that also gives them coverage on their personal property. That's the first level of peace of mind — knowing that it's available to you if there's an unfortunate event such as a burglary, fire, or other insured circumstance.
Personal property is handled slightly differently. The claims adjustor may start by asking you for a list of the things lost. You're allowed to reconstruct it from memory, but there is a definite possibility that you'll forget something, sometimes for months or years, after the claim was settled.
An interesting exercise is to visualize two rooms, possibly, the kitchen and main living area. Without being in the room, create a list of all the personal items in plain sight and those in the closets and cabinets. When you're done, go into each room to see what kind of things were not on your list and what the value of those items amounted to. You may find it's fairly substantial.
Remember, you're entitled to claim items regardless of how long it has been since you used them or even if you don't intend on replacing them again.
When filing a claim, the more "proof" you have to substantiate it, the better off you are. Receipts are great, but chances are, you may only have them for the big-ticket items. Photographs or videos of the different rooms are also great records that the items were in your home.
An itemized list of each room with a description of the content, cost, and date of purchase, supported by pictures, is ideal. This type of documentation will make filing and settling a claim much more manageable. The more documentation you have, the more likely you are to have a favorable settlement.
The more expensive the item, the better it would be for you to have receipts, serial numbers, and photographs. A simple count of some items like clothing will suffice, like four pairs of jeans, 24 dress shirts, etc. More valuable items of clothing like a cashmere jacket or a silk dress should be listed individually.
Depending on the frequency of purchasing new items for the home or possessions, you'll need to consider updating the list and photographs. Moving creates opportunities to get rid of things that haven't been used for years and acquire items for the new home. It is always a good idea to complete a home inventory after moving and settling into your new space.