Off the top of my head: - what problem it solves - what the trade offs are vs not doing it / other approaches - when, roughly, it makes sense to do - what t

Off the top of my head: - what problem it solves - what the trade offs are vs not doing it / other approaches - when, roughly, it makes sense to do - what the time / dollar / maintenance costs are I'm sure there are many more reasons but that's thinking about it for 30 seconds.