Labels intrinsically won't increase your storage limits as versions are already normally created when edits are made to documents automatically, the only difference will be the restrictions imposed on the label may prevent the trimming or deletion of some of those versions. The key we find is to determine what's the right set of restrictions and settings for your labels to ensure you're not over-retaining data you don't need but you still have any data you need.

I would look at the records retention policy from the business, but it is likely that this approach of putting on a Retention Label on documents that should be retained at the end of the project would be easiest. However, when the file that should be retained is done with edits, and has received signatures/approvals from the leaders seems like a natural point at which to apply the label. The labels themselves may work in the settings to say something like retain for 7 years and then automatically delete based upon the date at which the label is applied.

When I got my first SharePoint role, I worked with an Engineering project-based company so it was obvious that we standardize the SharePoint project libraries. This made it easy to create a new project site that was pre-loaded with folders, metadata/labels and structure. Some projects would require a few mods though.

Microsoft 365 Business Premium:

• Manually apply non-record labels
• Retention policies for Exchange
• Email archiving (50GB)

Our Customer Adoption Team has provided some great guidance for this in this blog post below and includes a link to a webinar where this is shown in more detail. Bottom line is you should set properties in the property bag to classify SPO sites and you can use user AAD attributes for ODB: https://techcommunity.microsoft.com/t5/security-compliance-and-identity/using-custom-sharepoint-site-properties-to-apply-microsoft-365/ba-p/3133970

At this time archiving policies are still managed through archive tags in the legacy Exchange Admin Center (soon they'll move to the Compliance Center too). An archive tag will work independently from any retention policies you setup on the mailbox so what you can do is create one archive tag for 2 years after item is sent/received and then create a retention policy (in Information Governance solution of the Microsoft 365 Compliance Center) to retain and then delete after 5 years.

Shared mailboxes need to be licensed to same as a user mailbox. To apply a retention policy, it needs one of the following licenses:

• Exchange online archiving (only mailboxes)
• Microsoft 365 Business Premium (only mailboxes)
• Microsoft 365 E3/G3/A3
• Office 365 E3/G3/A3

If you use an adaptive scope + a retention policy, you need one of the following licenses:

• Office 365 E5/A5/G5
• Microsoft 365 E5/A5/G5
• A pre-requisite license + Microsoft 365 E5 Info Protection and Governance

Those legacy features are included in SharePoint licensing. However as mentioned by Andrew below, in SharePoint Online we no longer recommend the use of these legacy features and instead recommend using our Records Management solution in the Microsoft 365 compliance center for managing records. Records Center is a deprecated site template at this point and instead of in-place records management which was the legacy way of classifying data we recommend the use of retention labels instead.

I am working with an organization that has over 100 retention categories and has a need for something like a Records Center for various reasons. The in-place retention labels work well for content with shorter retention periods. However, this particular organization has some labels that retain data for 20+ years.

I would respectfully suggest that Records Centers are no longer really suitable for managing records. However, there may be some organisations that find this legacy model useful.