How many environments do you need?

How many environments do you have for your software application, other than live/production?

Testing? Staging? UAT? Pilot? QA? Dev?

What do you use each one for?

What if you only had one pre-prod environment and production?

What if you only had production?

What if you only had one branch in your code repository?

No more merge conflicts.

No more confusion about which environment to test a change on.

How much simpler would that make things?