Adding jewelry and musical instruments to renters/homeowners

We’re interested in adding specific pieces of jewelry and some musical instruments to our insurance. Daughter has renters, hubby and I have homeowners. Some items have recent original purchase receipts, one has a 15-year-old old receipt, and most have none. Do we need to get appraisals for the ones that don’t have receipts?

And then we call our agent to add the items? Would we get reimbursed for the original purchase or appraisal amounts, or will they depreciate the items as the years go by? How much extra will it be, i.e., $10 annually per $1000 value or what? To complicate things, daughter is moving this summer to don’t-know-where. I would imagine where you live affects insurance premiums.

Thanks!