Topic: Travian Resource Development
I don't know if anyone else figured this out before...
When upgrading your resource fields, it is better to raise several low level fields than few/one high level. For example, to raise a field from level 4 to 5, the resource-cost-per-unit-increase is 176.8. To raise a lvl 3 to lvl 4, the cost is 166.4.
There's diminishing returns.
So if you have a choice between raising 2 smaller fields or one big field, go for the smaller fields.
(this is not considering build time)