That is a question to which you can get as many answers as you have people growing bonsai. In short.. It depends..
IF you think you will grow the trunk fat and then chop it, do not worry too much about wiring; Most of it will be cut of. If you attempt to thicken it with sacrifice branches, then yes, by al means add some interesting shapes in the trunk.The younger the branch, the easier to shape (Look at baby bending).