When we upgrade to new hardware at work we usually increment a number in the DNS name. For example. We have a server called database-2, that is slated to become database-3 in the coming days.

I haven't been able to find a good reason why this is good behavior. To me the work of trying to catch all end user machines, as well as all servers dependent on the database server is far riskier than simply moving the database and ip/name with it to the new hardware. A little over a year ago we spent several months of requests coming in, as infrequent users began using software that needed to be updated to point to a new DNS name. I am struggling to find answers as to why this is a good practice.

So the question. Why is using DNS names as a "server hardware version identifier" a good idea? What am I overlooking?

Thanks much.