My husband felt that some of the more fiddly aspects of fitting would benefit from some written instructions, not just pictures. He found some quite helpful advice on Youtube.
Net Promoter Score is a loyalty metric used as a KPI for customer experience, measured on a scale of -100 to +100.
To calculate the NPS, we first ask customers to answer the question "How likely is it that you would recommend this company to a friend or colleague?" on a scale of 0 - 10.
Customers who answer 0 - 6 are Detractors, 7 - 8 are Passives and 9 - 10 are Promoters. The NPS is the sum of % of Promoters - % Detractors.