About building farms or not.
I see a lot of post where people state that it's not worth it. I disagree.
I often go for at least one farm. It depends on the planets class and what i'm gearing it towards(research, economy or production). The cash the extra population brings in really makes a difference, however it does require that you have a high morale. You don't want to spam your planets with morale buildings. But two morale buildings and a farm brings in more taxes than three economy buildings and on top of that you have the extra population for defense and invasion.
In mid/late game i usually have 2 six billion farms on most of my worlds and only one or two morale buildings and taxes at 59%(at least). A population of 20 billion really requires a good morale and i would rather have 18 billion, but if you build older farms to reach this number you have to disable autoupgrade on the planet(if you have researched some of the "better" farms) and that's really a pain in the *** if you have hundreds of planets. So i stick to 20 billion.
You will usually have to build galactic achievements, trade goods(or you can trade for them) and mine morale resources(helps a lot) to have both a high population and high taxes. If you can't keep your taxes up then there really is no point in raising the over all population.
Watch out for the creativity bonus...it is a must have, but in one of my games it kicked in when i was researching the second last tier of farms and it gave me the "best" farms(those 7 billion ones). I had already set most of my planets up with two farms and i had over 70 planets(playing on an immense sized galaxy). 22 billion is just not worth it and if i had to turn off autoupgrade on every single planet and then upgrade the other buildings manually, well that would take forever. I had to manage with one farm on each world and it annoyed me immensely through out the rest of that game.
By the way i always use bonus tiles with 100% or 400% food production. Just put some "old" farms on 'em, saves up tiles. I turn the autoupgrade off on those planets, so one does have to micro a bit more.
It would be nice if the penalty to morale weren't so severe on higher class planets. Then maybe one could actually find a use for those buildings that give a % bonus to food production.
But what are your thoughts on the subject?