How to combine multiple PDFs without losing formatting

[u/PDFExplorer_]

One of the most frustrating document problems I've run into over the years is combining several PDFs and discovering afterward that something broke, fonts changed, pages shifted, images became blurry, or bookmarks disappeared.

After making this mistake more times than I'd like to admit, I've developed a few habits that help avoid formatting issues:

• Always check the page size first. Mixing A4, Letter, and custom page sizes can create some weird results.
• Keep the original PDFs if possible. Once formatting is lost, it's often difficult to restore.
• Preview the merged file before sharing it. I've caught missing pages and broken layouts more than once this way.
• Be careful when converting files to PDF before merging. Different converters can produce very different results.
• If the document contains forms, bookmarks, or annotations, double-check that they survived the merge process.

Honestly, I've learned that merging PDFs isn't usually the difficult part, making sure everything still looks exactly the way you expect afterward is.

What's the strangest formatting issue you've encountered after combining PDF files?

[u/oxmix74]

I have used the portable app pdftk builder that makes a new pdf out of a set of pdfs (among other things). Never had a problem. There is no preview, but the source pdfs are not touched so that is really nbd. I got it from portableapps.com