I am a bit confused here, what difficulty level are we talking about? Survival is always priority number one ofcourse, but beeing so hesistant against building even markets would atleast put me in a position were I would have a hard time financing any proper defenses, since all thoose warriors and workers that would pop out cost money.
Another important point other than when the market-investment breaks even is the fact that a market finances the upkeep of more troops, IMO.
I mean, in general, take a minute to think the investment you are about to make through. A market, costs 60
, while a warrior costs 25. However the net +2
would finance another two warriors (~), or contribute to another city. The merchant specialist is ofcourse also an asset, given food is avalible.
So, do you need 2 more warriors short term or improve the foundations of a larger empire/army long term? It is all matter of risk in the end, I guess.
Another problem is how to specialize cities. Reading through topics most people say: Don't build everything in one city: specialize them. How? I need some buildings just to survive (such as an infirmary) which needs hammers, which needs people. So I tend to spam farms and mines and almost always forget to build cottages which is why I heavily rely on Aristocracy. Then again: If there are no rivers nearby or mines I can't either build farms (which results in no people) or no mines (no hammers) so production is very slow. Red smileys and the need to work on tiles keep me away from just using specialists. Any specialist keeps me away from working on farms thus preventing me to get new people which could possibly be specialists (it's a vicious circle ).
Well if you cannot build farms, build cottages? Perhaps you are playing on too large maps? While learning the game it might be harder to have a vast empire, or atleast you should focus on a couple of cities and really plan them through.
And tiles and specialists are not separate unvierse. All citicens require food, but once you can feed the population you can keep happy there is nothing preventing you from assigning a specialist, if you need the particular gains they give.
Catch-all strategies might be helpful along the way, but myself I prefer to try and learn more instead and sort of make my own diagnostics over my often failing empires. That way, you learn something every day
And why keep all borders closed? Not every AI is an enemy, nurturing a few friends can be very rewarding; as buffer-zones (think warzaw-pact), as trade partners (resources, techs and trade routes (very important)), as religious friends fueling your possible religious wonder, and so on. The main drawback of open borders is that they can have a negative impact on other diplomatic relationship. I wouldn't trust the incompetent AI to craft any smart plans with the information open borders might provide them.