7 good reasons to create a new document library. (And 3 bad ones)

When talking to end users, I often notice that people think they need to spread their documents over various document libraries to create meaningful groups of documents.
In general, I suggest them to use one document library as much as possible, and use metadata to organize documents. This will have the advantage that they have the complete set of documentation with context and do not have to click on individual document libraries to find a document they are looking for.

But in the following situations it may be better to use multiple libraries:

1. Different audiences. 
   A common example is a library only accessible to the Management Team or the Project Team, which contains documents-in-progress or documents with confidential information. While the content belongs to the site in question, you do not want all users to see those documents. I always suggest to add this information (“only accessible for the Project Team”) to the description of the document library, so the site owner does not forget.
   In theory you could use a secured folder,  but only if you add “restricted” to the name…but you want folder names to be short.
2. Very different set of metadata.
   If one set of documents needs to be organized by topic, review date and document owner, while another set needs organizing by topic, location and business process, you want different libraries. In theory you could use one, but it would mean that the upload page becomes a long one, and too many fields will be optional.
3. Complex or too many metadata.
   I have once had to create a library to document all of a factory’s processes. They had many metadata columns, but that could be easily accomodated. However, the documents had to be displayed on several pages, with a connection filter for easy display and retrieval. For some pages I needed more than the 10 filters that SharePoint allows in a view, so after many experiments I had to create several libraries. The limitations of the views were the problem, not the library itself.
4. Different contributors or ownership.
   If you have contributors or owners from many different parts of the organization, or a large difference in skills and experience, it may be better to set up a library for each team. That will avoid misunderstandings and mishaps in maintenance of content, users, metadata and views.
5. Advanced settings.
   You may need versioning, an approval workflow or autodelete after 1 year for a small subset of your documents only. In those cases, it is better to have one library per advanced setting.  Advanced settings often have to comply with company policies and they always need extra maintenance, so the less documents you have with those settings, the better.
6. Too many documents. While the technical SharePoint limit is 5 million documents per library, in practice the performance of your platform may not be able to handle that.  Also, you may experience issues with backup and restore of libraries with many items. You need more libraries if you anticipate you will have more documents than the recommended number allows.
7. You can not add metadata. When a team wanted the ability to upload documents by email, I thought it would be better to create a separate library. Beacuse with upload via email you have no option to add metadata while uploading. The only options for any structure are to add metadata afterwards (which is likely to be forgotten), or to group the documents in folders “by sender” (which is redundant since “Created By” is added by default) or “by email subject” (which is risky unless contributors are very systematic in their email subjects).
   So, in this library we used “by email subject” and ended up with folders named “visit report”, “customer visit report”, “meeting report”, “customer meeting 25 March 2012″, and similar names, often containing only one document. I was happy to separate that embarrasing library from the other documents . Needless to say I try to discourage the use of email-enabled libraries, unless the contributors use a very strict naming convention.

The sad result of grouping by email subject

There are also some occasions when you think you need a different library, but really don’t:

1. You need more templates to choose from. In earlier versions you could ony add one template to a document library, so when you needed a choice of templates, you had to create a new library. This is no longer the case; you can create several Content Types in one library.
2. Single-topic notifications. This occurred when a team wanted Alerts for one specific topic only and they thought it could only be done by creating an extra library for this topic. Luckily I could show them in time that you can set an Alert for a specific view, as long as the view contains a filter.

You can set an Alert on a filtered view

3. You do not want to add metadata. You think that crawling 10 libraries every time you are looking for a document is less work than spending a minute on ticking the right boxes during upload? I challenge you to a test with a timer! Besides, it means that you are not exactly helping your audience either – they will also have to spend too much time looking for documents.

Have you experienced any other situations to add to one of these lists? Would you do it differently? Please share!