A disavow file, a bulk redirect import, a URL inspection queue — each has a cap, and exceeding it produces either an error or, worse, a silent truncation.
Silent truncation is the real risk
Some tools accept a file over the limit and process only the first N rows without saying so. The upload reports success and a third of the work never happened. Nobody discovers it until the results are inexplicably incomplete.
Split to a size under the cap
Batch below the documented maximum rather than exactly at it, so a trailing blank line or a header row cannot push a batch over.
Track which batches completed
Number the batches and record each as it succeeds. When something fails partway through a long series, you resume from batch seven rather than starting again or, more commonly, guessing where you got to.
Try it: Split List into Batches on SeoWolf's Notepad.