After-sales services encompass all the services offered by a manufacturer or distributor to its customers after a product purchase. These services include installation, user training, personalized advice, servicing, maintenance, troubleshooting, repairs, warranty claims, the provision of relevant information, and 24/7 telephone support. Sometimes, these services are referred to by the acronyms P (parts), MO (labor), and/or D (on-site service), which specify the scope and nature of the associated warranty.