In 2v2 normaly the game requieres building TC faster, since all-in rushes usually don't work as well as in 1v1.
In 1v1 it depends on your strategy. There are different BO's
If you go all in, first build siege--> Mangos and Thumb Ring/Balistics ASAP. Then later you can build more TC when you can.
If you go little more defensive you can build a second TC as soon as you hit castle and make balistics wait a bit.
In 2v2 :
If sc--> kts build 2 tc right away
If arch-->crossbow you probably can build 1 tc and get balistics, you gonna need it. Then make third tc, it won't delay it too much, maybe 2 min.
If dr-->FC you probably won't be able to afford TC right away. Focus on getting some snipes out of enemy's vills and make TC when you can. In this case balistics/thumb ring won't be an option soon, so probably make second tc first.
It all comes down to what strategy you wan't to use really, I don't think there is a written rule about how to behave/play. Just don't screw up with the Build Order. (Eco ups always in right time, the order in which you put your buildings is far more important than in which second you put your TC imo)