Having been asked to help build development and test environments in AWS for a client who is looking at moving all of their on premise database servers to the cloud, the first task I was assigned was the installation of SQL Server on a development server.
I asked if they had an automated build process? No - was the answer.
With potentially over 50 SQL Servers to build (non-prod and then prod) I recommended that we build an automated install to ensure a consistent and quick build. No - was the answer.
Creating an an automated installation would also save time (and therefore money). No - was the answer.
So we will hand build every SQL Server, although we may cheat a bit by cloning the VMs if possible.
An automated installation process these days is easy. A little bit of PowerShell, some T-SQL scripts and you can install SQL Server with the options you want, install latest Service Packs and CU's, SSMS and then customise this installation with your T-SQL scripts (e.g. Backup and maintenance, alerts, operators, database mail etc).
In reality, you more than likely have most of this scripted anyway, so it is just a matter of creating an installation wrapper and then calling each component. So automate if you can!