At work we need to distribute daily changes to a dataset, so we have a series of daily deltas. If a new client is brought up, they need to apply all the deltas to get the current dataset.
This is time consuming, so we optimized it by creating "base versions" every month. So a client only needs to download the latest base version and the apply the deltas since then...
Which is what accountants call "closing the books". Once all ledgers have been reconciled, old ledgers can be archived and you go forward from the last closing.
Forensic accounting, incidentally, is when something went badly wrong and outside accountants have to go back through the old ledgers, and maybe old invoices and payments and reconstruct the books. FTX had to do that after the bankruptcy to find out where the money went and where it was supposed to go.
This is time consuming, so we optimized it by creating "base versions" every month. So a client only needs to download the latest base version and the apply the deltas since then...