Talk:Gold Mine/@comment-108.241.0.22-20130223201103/@comment-174.51.54.224-20130307170139

I'd upgrade them up side by side with defense and lab upgrades, but with a preference to collectors. The only thing to keep in mind (not that this even effects gameplay) is you will inflate your experience by 10-12 levels by upgrading all your resource collectors together. The extra passive resources are worth it to me though. With all your mines at lvl 7 you'd pull in ~230k a day vs 432k at lvl 11.