Is it expedient to use a subdomain for test services and servers in the company's local network?

Question

Domain Name System

Good time.
There is a company's local network with a certain number of services. Most of these services have clones for testing new configurations, updates, and more.
At the moment, these clones and their components have the following FQDN:
mailT.domain.ru
or like this:
mail-test.domain.ru
That is, a letter or word is added to the original name, in this case T or -test.
I would like to bring this collective farm into a separate subdomain (and even into a separate subnet), which would be something like this:
mail.test.domain.ru
I want to hear about the pitfalls of this way of managing services in the local network.

Answer 1

As a rule*, no pitfalls (well, except for the indignation of developers that the domain has become longer) should not arise.
Moreover, for example, I do exactly that...
*(depending on the idiocy when processing configuration parameters / rewrites / other processing of incoming parameters by the application)