Merging separate scans into a single PDF turns a scattered set of individual pages into one coherent document — the difference between sending someone five separate files and sending them one properly ordered document.
Why order matters
A good merge tool sorts pages by capture date or lets you manually reorder them before combining, since a multi-page contract or form needs to read in the correct sequence, not just be bundled together.
What to check before merging
Confirming each individual scan is already dewarped and cropped correctly before merging avoids baking a skewed or poorly cropped page into the final combined document, where it's more annoying to fix.
What a good merge preserves
Image quality shouldn't degrade during the merge step — a properly built merge tool combines the existing processed pages directly into a PDF container without recompressing or resizing them further.
Can you merge scans taken on different days into one document?
Yes — merging is typically based on which scans you select, not when they were captured, so combining pages scanned across multiple sessions into one final document is a normal use case.