FrozenJoe
You got a solid advice above from experts. However, I found accidentally what experts have mentioned in the posts is that for those who will be rooting cuttings from their own plants or other accessible plants, the bext time to take cuttings is when the plant is just breaking dormancy. Cuttings at that time rooted for me in rooting soil much faster (with plastic bag small dome). This also allows one to take the plants outside in shorter period then holding it inside during the winter (until mid to late spring). One may say that why not air-layer then. That is good suggestion but air-layering normally gives you one plant per branch but one can cut the branch for more cuttings and so more plants (for a green thumb).
But if you are doing cuttings received from others then any time is good as long as the cuttings remain viable.