I prefer to wire and shape trees in three stages. The first stage involves the trunk and larger branches. The second phase incorporates the secondary branches and the third is the fine wiring and placement of tertiary and finely developed, ramified branches / twigs with leaves or needles. Each phase lasts a minimum of a year and includes at least one growing season. This video shows some intermediate wiring.
Why? I do find that this way produces a better, more refined product and it gives the tree more time to adjust and recover from harsh bends. My gut instinct tells me that it might also be better for sap flow in especially Junipers compared to trees that undergo a full wiring, bending, cutting and sometimes even a full repot in one session. I do hope that this last scenario is not a common thing.
I might have to change this as I now live in a warmer climate with a longer growing season. Time and attention to growth patterns will tell.