A few weeks ago I decided to focus lots of upgrade time on my Cement Factory as the discounts apply for the rest of my Modern War gaming. So each 1% reduction in upgrade and construction costs took probably on average 2 days to come through. Was it a complete waste of time to upgrade it five times (which I have done) as opposed to upgrading other money producing buildings that over a similar time period would now be producing much, much more money?
I suspect I've just answered my own question!
Anyone had a similar debate / done the same thing?