I think this is a useful topic for any player looking to improve their game, up to those looking to optimize finish times: what is the breaking point at which a given building becomes worthwhile or not? There is certainly some necessary context to the question. For example, in pursuing a Science Victory, a Library is required in every city; however, back in the days of the Deity series I formulated an 'Illiterate' strategy that proved successful in some fast Domination games. For simplicity, I'll assume the pursuit is a Science Victory. Buildings that impact production and food should be the easiest to quantify. So, to gauge interest in the topic, let's first consider the stable, as there was a post in a recent thread that caught my eye: Stable Cost 100 hammers Maintenance 1 gold/turn Value +1 production per horse, sheep, and cattle *need a pasture on one of these resources to build, but the +1 production is based on the resource, not the pasture, so the bonus does not rely on further worker action, only tile expansion At what point does this building 'break-even' with regards to it's main output? (Note, this is a slightly different question than whether it's worthwhile, focusing only on 'getting back' the production invested) At 100 hammer cost, you 'get back' the production costs in: 1 resource = 100 turns 2 resources = 50 turns 3 resources = ~33 turns (34th turn. I'm rounding off on these for simplicity) 4 resources = 25 turns 5 resources = 20 turns 6 resources = 17 turns The 1 gold/turn is not prohibitive, but maintenance should be considered in this analysis. If we consider a gold to hammer value ratio of 4:1, the 1 gold maintenance reduces the stable value by an equivalent of 0.25 hammers per turn. As such, the return value becomes: 1 resource = 0.75 hammers/turn = 133 turns (134th turn) 2 resources = 1.75 hammers/turn = 57 turns 3 resources = 2.75 hammers/turn = 36 turns 4 resources = 3.75 hammers/turn = 27 turns 5 resources = 4.75 hammers/turn = 21 turns 6 resources = 5.75 hammers/turn = 17 turns The intangible consideration is the 'missed value', had you instead put this production into another building. This is where the player needs to make the best in-game decision for themselves. The number of turns cited above will have a different relative valued based on the estimated length of the game: a 300-400 turn game gives a lot more turns to derive value from the Stable, whereas a 200-250 turn game will see 'essential' buildings (ex. University) become available to build sooner. At this point I am going to estimate whether or not the building is worthwhile based on whether it can return it's equivalent production cost 1, 2, or 3 times over before the game ends. I will suggest that 1x is a definite 'no' (because of the missed value in building something else), 2x is a maybe that should be carefully considered, and 3x is a definite 'yes': # of resources: turns required to reach 1x, 2x, 3x equivalent return 1 resource: 133, 266, 399 turns (note this is turns from completion of building, not total game length) 2 resources: 57, 114, 171 turns 3 resources: 36, 72, 108 turns 4 resources: 27, 54, 81 turns 5 resources: 21, 42, 64 turns 6 resources: 17, 34, 51 turns I currently view having 3 resources and being able to start production before Education as the necessary requirements to build a Stable in my games. A common scenario involves reaching Education before finishing the Stable. When this happens, I evaluate how many hammers remain to build the stable, how quickly I'll get those hammers back (i.e. not the full 100, just the remaining amount), and whether finishing the stable will actually delay the University, and if so by how many turns. Usually, if I can get over 50% of the stable built before hitting Education, it's worthwhile to finish the stable before starting the University. My estimate is that the breaking point for building a Stable is having either 2 or 3 resources available by the completion of the building*, depending on game length and the point at which you can start production. If there is interest in this topic, I could cover some other buildings or related questions. Input from other players is of course welcome. *you can also estimate an average, if perhaps there will only be 1 such resource available upon completion, but 4+ resources later in the game. We can also further complicate things by factoring in the cost of buying a tile to get a 2nd/3rd/+ stable resource, which I'll mostly leave alone except to suggest that if you're going to purchase such a tile, buy it earlier rather than later to get more return value.