If you've rolled out Microsoft Teams and your team is still defaulting to email for everything, you're not alone. Most small firms end up with both tools running in parallel, with no clear rules about which to use when. The result is that important things get buried in both places, and nobody's sure where to look.
Here's a practical way to think about it.
Email is for external communication and formal records
If you're communicating with a client, a vendor, a subcontractor, or anyone outside your organization, email is almost always right. It creates a clear record, it works with any inbox, and there's no expectation that the other person has any particular software.
Email also makes sense internally when you need a paper trail — sending a proposal for internal review, notifying the team of a policy change, or communicating something that needs to be archived and searchable later.
Teams is for internal collaboration that doesn't need to be a meeting
The Teams sweet spot is conversation that would otherwise result in a meeting or a long email thread — working through a question, getting quick input on a decision, coordinating on an active project. It's lower overhead than a meeting and easier to follow than a reply-all chain.
The channel structure in Teams also lets you keep project conversations organized without clogging up anyone's inbox. A project channel is visible to everyone on that project, searchable, and persistent — something a group email thread never quite manages.
The part that trips people up
Most teams struggle not with the tools themselves, but with consistency. When half the team uses Teams for everything and the other half lives in email, you get fragmented communication and people missing things.
It helps to establish a simple default: Teams for internal collaboration, email for anything external or formal. You don't need a long policy — just a shared understanding that people can actually stick to.
One thing worth knowing
Microsoft 365 stores Teams messages separately from email, and both have retention and backup implications. If your firm is subject to any records retention requirements — or if you're working toward CMMC compliance — how you use these tools matters beyond just convenience. That's worth a conversation with your IT team if you haven't had it.