forgive my noobiness, but what is a tech start? does anyone have more info on this?

As a commie indy, when should I start spending cash on industrial tech? It's really expensive right now, but I feel like even a slight percentage is going to help me a lot. Should I wait to buy tech until reaching a certain amount of acres?

I used to play but found it to be too intense. Waking up at 4 am to make my attack in war just so I could wake up at 8 to see I was chained to 100 acres made me a little sad.