You can run your whole business through a free email account if you want. Plenty of people do. The hidden costs of that choice are easy to miss until you trip over one.
You Do Not Own Your Address
Free mail providers can suspend accounts. Not often, but when it happens, there is no appeal process worth the name. One automated flag and every invoice you ever sent, every contract thread, every customer reply, is behind a login screen you can no longer reach.
When your mail lives at a domain you own, that risk goes away. Your provider can have a bad day. Your email still works, because you can point the domain somewhere else by lunchtime.
You Are Advertising Someone Else
An address at a free provider tells your customer that you have not invested in your own identity yet. Right or wrong, that signal gets picked up, especially by other businesses deciding whether to work with you. A business address on your own domain is a tiny thing that changes how you are perceived.
You Are Training An Advertising Engine
Most of the big free providers are free because their business model involves knowing what you care about. The inbox is the funnel. Every message you read, every contact you have, every receipt you store, becomes a data point. For personal mail, some people are happy with that trade. For a business inbox, it is rarely the right answer.
Switching Is Less Painful Than You Think
The reason people put off moving from a free provider is usually the migration. They picture days of lost mail and broken filters. In practice, with a provider who does migrations properly, moving a mailbox takes minutes and nothing is lost. We move people from the big free services every week. It is part of what we do.
If you have been running your business through an address that says gmail or outlook, it is worth a Tuesday afternoon to sort out. The peace of mind starts the moment the switch completes.
