Huangcheng Jewelry requires customers to add 20% new gold when exchanging old ones for new ones. For example, if the original weight of gold ornaments required by customers is 10g, then at least 2g of gold needs to be purchased to replace the old ones. The newly bought gold is calculated according to the quotation in the store. The relatively troublesome thing is jewelry inlaid with diamonds and gems. Because the evaluation value of jewelry may be biased, there are not many silver shops that offer this kind of jewelry trade-in business. Even if this business is implemented, it is mostly limited to the jewelry sold in our store. For consumers, calculating the residual value of this kind of jewelry will be very different. For a lady's diamond ring with an original price of about 20,000 yuan, the depreciation charge in the original store is generally only 200~500 yuan, but in other silver shops that offer trade-in business, the depreciation charge is usually above 10%, which is not very cost-effective.