Running a winery is a a lot of work. Growing, making, storing, bottling and last but by no means least selling the product. It's no wonder that keeping up with their TTB compliance is often little understood. US wineries are required to file certain reports to the TTB, and one of those reports, the 5120.17 is always required regardless of their activity or lack thereof. (this is the still commonly referred to 702 report)
The 5120.17 report is what lists all the gallon amounts connected to the different types of winemaking activities that occur at your winery site and the TTB has three levels of filing requirements for this report, annually, quarterly or monthly. By the way the two other most common TTB required reports are the excise tax return and certificate of label approval (COLA), however both of these reports are only required based on reporting gallons on specific lines of the 5120.17 report.
The qualifications for determining whether your winery can file the 5120.17 report once a year, quarterly or must submit it monthly are based on (1) the maximum (in bond) gallon amount held at your site during any month in a calendar year and (2) the total excise tax liability for the previous and current year.