What is the best way to store my files (e.g. to use them at home and at work)?

One file for all articles

It is most convenient to keep one large file for all articles that you publish. This will contain all references that you have used and PDFs that you have read. This way you never have to search long for a reference.

Two parts: *.enl and *.data

An EndNote file always consists of two parts, a file * .enl and a folder * .data. The two should always stay together and keep the same name. If you change the name of one, you must also change the other.

No File > Save

EndNote does not have File > Save, only File > Save a Copy. EndNote immediately saves all changes. Only use File > Save a Copy to actually make a copy, for example as a backup.

Save to external hard disk or USB-stick

If you want to work with the same EndNote file at home and at work, it is useful to save it on a portable hard disk or on a USB stick.