PDF is probably one of the most trusted and used format for documentation around the world. This is clearly regarded as one of the most appropriate formats for official and even personal document management. Especially professional matters require electronic documents in such a format that cannot be easily altered since the record is maintained for future projection, referencing and even archiving.
Moreover, when it comes to easy sahareability through emails and even external hard drives, still PDF is the top priority of businesses around the world. PDF files come in very handy, retain their format and data remains the same, the text cannot be easily altered. This is a universally compatible format that is widely accepted.
As mentioned earlier, PDF is certainly the most used format around the world, most businesses maintain their official records in this format that amounts to hundreds of thousands of pages long files. In case where you have larger PDF files, one may require to filter out the data where some pages might be required and the other ought to be left or simply deleted. Given the liberty of deletion, many archived files can be re-used and benefitted from.