Yes, you can sign the contract on different products to give better services of the products. There are many Home Improvement Service Providers provides after sales or installation services. The services include maintenance and reparation of the products as signed by the Home Improvement Service Provider and the company. The Home Improvement Service Provider can give guarantee on the products as per the supplier agreement.
There are various products like electrical and electronics products are under the guarantee period. Once the guarantee period get complete than you need to sign a guarantee agreement with the customer.
