I have an auto-repair shop in New York. We install tinted windows in various vehicles upon client request. Is this job subject to sales tax in New York?

The short answer is that it depends if the tinted film will be placed on new or existing windows. Tinted windows in connection with the original installation or complete replacement of a window constitutes a capital improvement as per New York State Sales Tax Law Section 1101(b)(9)(i). Capital improvements are not subject to sales tax in New York State. However, if the tinted film is installed on existing windows, it would be considered servicing real property and subject to sales tax as per NY Tax Law section 1105(c)(5). Please note though that if the client isn't subject to sales tax, you still need to obtain a Certificate of Capital Improvement (Form ST-124) from the customer within 90 days of the completion of the work and retain the certificate as part of your records.