Naming convention for your devices?

As title states, how do you name your networking devices?

Currently we do it differently depending on type of equipment.

rtr-1.street.city.technology.dns-suffix - this would be a typical CPE name.

fw-1.customer.dns-suffix - a firewall could be placed anywhere :/.

nex-1.datacenter-room.dc-location.dns-suffix ( could be a datacenter switch where customers or shared services is connected )

My biggest problem is that we have been part of a company merge 6 smaller ones, getting into 1 big. And still this day a few years later, we still use different naming conventions. Seems like a subject everybody is afraid to talk about.