Fort vs. Trench

[MichiganKOM]

Forts are pretty expensive in this game, and trenchworks aren't. Even with the slight advantage a fort has in hit points, is there a good reason to build one? Would it be best to build the best possible trenchworks before building a fort?

[Usaball]

I think you should only build forts around your capital, major cities, and where you have a lot of units, because artillery will bombard your units, and larger armies will attack yours, giving you a major advantage. Forts do take a very long time (30 turns) vs trenchworks, but I would start out with trenchworks, then take the time and effort to build forts around vital cities.