Let us be honest about the benefit, because it is usually oversold. Nobody
has ever chosen a plumber because their address ended in
@monplombier.ch rather than a free webmail. The gain is not that
you win clients. It is that you stop losing a few, and that you stop building
your business on an account you do not own.
The part that is about perception
For a quote sent to a company, an address on your own domain removes a question the reader did not know they were asking. That is all. It is a small effect, and it is real — most visible when you are one of three quotes on a desk.
The part that is about ownership — and it matters more
A free mailbox belongs to the provider. If it is suspended, if the recovery phone number is an old one, if the account is used for something that triggers an automated block, your professional correspondence goes with it. There is no support line for a free account.
An address on your own domain is different in one decisive way: the domain is yours. Change provider and your addresses follow. Your clients keep writing to the same place and never learn that anything happened.
What it takes
Two things: a domain name, and a mailbox on it. Both are add-ons here — the
domain is quoted at checkout because the price depends on the extension, and
professional email is 4 CHF per month. You can start on your
included .names.legal subdomain and add a domain later; nothing
in your site needs to be rebuilt.
One habit worth taking on day one
Use the address. An address created and never used is worse than none: the first message a client receives from it lands months later, from an unfamiliar sender, and goes to spam. Send your quotes from it from the first day.