Zotero strongly recommends you back up your library.
Syncing is not the same as backing up because only the most recent version is stored in the cloud (your zotero.org account). If you accidentally delete something from your library, it is irretrievable.
Add an additional email address so you can continue access if your original email account becomes inactive.
If you used your NPS email originally to sign up, you can easily switch to your personal email account as primary after you leave NPS.
Go to zotero.org > Settings > Account
You can buy more storage beyond the free 300MB limit.
|Storage Limit||Cost (USD)|
You can reduce the amount of storage you use by removing your PDFs from Zotero, and linking to them instead. Remember that you will then lose the ability to search your PDFs.
Use the paperclip icon.