Eric,I agree Adair and generally do unwind the small wire, especially Al. Copper is really hard to unwind though, and even at small gauges you can risk breaking the branch or causing damage to the bark while trying to unwind. The other advantage to unwinding Al wire is you can reuse it sometimes! Shocking to some purists who have money to burn I am sure... But wire is hard for me to find without ordering online and it can get a bit pricey. I reuse some of the small wire I unwind from time to time and with Al it works just as good the second time without needing to be annealed again. Copper is so hard after it sets, not only is it difficult to unwind but it has to be annealed again if you want to try to reuse it...
The other thing that makes it easier to cut off though is- sometimes when you apply the wire, you are doing it to a freshly trimmed tree with somewhat sparse growth on it, or a deciduous tree that is dormant perhaps... And by the time you remove the wire, your tree may have grown a bunch of new foliage which is suddenly very close to the wire and easily broken off as you try to unwind it! In those cases, when removing large wire and generally most any size of copper, I am using my wire cutters to take it off... Which is about 40-50% of the time I am removing wire I'd say.. So it is a very important tool I have found.
Someone mentioned having bought just some regular hardware store wire cutters, and those are fine when applying wire. To cut it to shape... BUT, after believe the same thing and using regular wire cutters for years, I found that there really is so ring to the rounded tips Bonsai wire cutters have. The hardware store tools almost all have a sharp, pointed tip and to get it in close enough to the tree to cut the wire all the way that tip will invariably bite into the bark much more often than the rounded tip cutters you get for Bonsai, AND the long, thin design of the Bonsai tool allows you to get into tight/ tough to reach spots that the hardware store tools are just not made to get into.. May seem like minor reasons to spend extra on a tool, but once you get a BUNCH of trees that need wire removed, you will be glad you have a good set of cutters to do it! The Kaneshin tool is very high quality IMO and not that expensive compared to other quality Bonsai tools.
Copper doesn't "set". It does work harden. Which is why I try to bend it as little as possible as I apply it. It's bent a little more as I shape the branch, so it gets a wee bit stiffer when I do that. But from that point on, it stays the same stiffness. Until I remove it.
I have found that the SMALLER the branch, the more important it is to unwind the wire. The small branches are much easier to accidently cut when trying to cut wire.
Yes, it's tedious. Like any skill you have to practice doing it. I, too, resisted when Boon first told me to remove wire by unwinding. But, I have mastered it. And it is the better way. It's the way the best professionals in Japan do it.