In current behavior, services get created when you call them with :GetService()
They don’t always exist. Though some behavior changes are coming soon.
These changes are visible only, shouldn’t have any code facing changes.
For the OP, it depends on what specifically you mean. TeleportService is a remote service that they might be tracking the stability of on their own, like if there’s a lot of teleport failures recently they’ll report that it’s unstable.