Hi there, Elegant Jewel & Gift.
Thanks for reaching out to Seller Forums with a great question!
As mentioned, FBA accounts for inventory on a FIFO basis across our entire fulfillment network. In essence, this means that, for the purpose of determining how long inventory has been in our fulfillment centers, we will account for a sale or removal of a unit by deducting it from the inventory that has been in our fulfillment network the longest, regardless of which physical unit was actually shipped or removed.
You can read up on more information on how FBA’s Long-Term Storage Fees are applied, and when, at our [FBA Long-Term Storage help page|https://sellercentral.amazon.com/gp/help/help-page.html/ref=ag_200684750_cont_scsearch?ie=UTF8&itemID=200684750&language=en_US].
Since Amazon has set “Inventory Cleanup” dates of August 15 ^th^ and February 15 ^th^, keeping these dates in mind can help you in determining when to restock slow-moving inventory.
Rather than charging Long-Term Storage Fees on a rolling basis, we simply calculate the inventory quantities that have been in our fulfillment network for more than 6 months or more than a year on the Cleanup dates. With that said, you could send inventory units to Amazon 5 months prior to an Inventory Cleanup date - we’ll use the August 15th cleanup date as an example. Should none of those units sell, they will not accrue LTSFs unless they remain in our fulfillment network until the following Cleanup date of February 15 ^th^, as they were only 5 months old at the time of the August cleanup.
I hope this additional information helps and I want to wish you an excellent day ahead!