Most people use one email address for everything — every game, store, forum and service. It is simple, and it is also a single point of failure. Email aliases offer a better approach.
What an email alias is
An email alias is an address that delivers to your real inbox without being your real address. There are two common forms. Many providers support "plus addressing": adding +something before the @ creates a variant that still reaches you. And alias services generate entirely separate, random-looking addresses, each forwarding to your inbox, that you can switch off individually.
What aliases protect against
Aliases give each account its own address, and that has real benefits. If a service is breached, only the alias you gave it is exposed — not the address tied to your other accounts. If you start getting spam at one alias, you know exactly which service leaked or sold it. And because every account has a different address, a leaked email-and-password pair from one service does not even point an attacker at your other accounts, since they do not share an email.
The link to credential stuffing
This last point matters. Credential-stuffing attacks rely on the same email-and-password pair working across services. Unique passwords already break that. Unique email addresses break it again, from the other side: even the username half of the pair is different everywhere. It is defence in depth for the cheapest possible effort.
How to start using them
You do not need to convert everything at once. Start with new sign-ups: give each new service its own alias. For existing accounts, change the email on the ones that matter most over time. Keep a note of which alias went where, or let an alias service track it for you.
The takeaway
One email everywhere makes every account easier to link and one breach easier to spread. Aliases give each account its own address, contain breaches, reveal which service leaked your data, and add a second layer against credential stuffing. It is a small habit with a genuine security payoff.