Hi please enlighten me:

Is tech phase required for any country to obtain their respective key techs (agri for farmer, indy for commie)?

Why would a techer tech indy and sells them off to public market rather than focusing on bus/res?

- Thanks.

A tech phase isn't required, but they do need to obtain their respective techs to be competitive (in one way or another, such as by not grabbing for a day and using their indy/farmer/cashing income) somehow. Just not necessarily by actually teching.

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A techer generally techs whatever tech sells for the highest price on the market, in order to maximize his income.

Because res/bus techs also increases the per-turn revenue, the techer also needs to take this into account. Once the techer has over a certain amount of res/bus techs (say 165% or above), it is generally the case teching the higher priced techs will generally get more money.

Thank you!

Also keep in mind that you want to pick up some tech allies to work with you.