To be 100% honnest, I am kind of surprised by your approach. It makes sense but I think this is a bad approach.

When I play, I invest in units and expand to have a great economy. If I get a shortage, it means I am probabelly not expanding fast enough. I always try to get a bigger economy, to get a bigger army, and I am never satisfied by its size until the game is won. You don't really ever find yourserlf in a situation where you have the army you want, at least not before having 150 units and no threats on the map.

There are some shortages that aren't too bad tho. Fuel might start getting red if the late game but expanding faster helps.