This topic has come up several times in Succession Games, and I have seen players champion both strategies.
In the beginning of the game (ie in the first 1-2 turns in the entire game), you have one worker, and a newly settled city. There will occasionally be a nice tile such as grassland with wheat on it, which most people irrigate. Assume the worker is on this tile, and it has access to irrigation. The question is: Do you Irrigate a tile first, or build a Road?
In the beginning of the game (ie in the first 1-2 turns in the entire game), you have one worker, and a newly settled city. There will occasionally be a nice tile such as grassland with wheat on it, which most people irrigate. Assume the worker is on this tile, and it has access to irrigation. The question is: Do you Irrigate a tile first, or build a Road?