I've noticed that a lot of the top players build 3 pgens around each of the first 4 mexes, particularly on Seton's. Why is that? It seems like it just gives a very minor energy discount, or is it enough to be significant?
I usually leave the surrounding space empty for future mass storage. Is that a noob mistake?
EDIT: just had a thought. Do the surrounding pgens make the upgrade from T1 to T2 cheaper?