I've been trimming bushes for a customer for many years. About eight years ago, they installed 14 small arborvitae. At installation, I recall they were about three feet tall, perhaps a bit more. Every season, I've trimmed them, one time per season. This Spring and early Summer, they didn't grow much, but the homeowner wanted them trimmed up like usual. Every year, this job seems to be a killer for me. It is on the SW corner, and I'm always there in the afternoon -- hot part of the day, sun beaming on the work area full blast. But, today was only low 80s. I just seem to be have trouble with this task -- hard work, takes me longer than I think it should. I'm using a Stihl HS80. Usually, I'm taking off only a little growth because the insides are all browned out. A small slip, cutting a bit too deep, and the ugly really appears easily. They are only about six feet tall by now. I had a helper, who did most of the cleanup. We laid tarps to catch most of the clippings. The bushes are planted in a recently mulched bed of fresh bark mulch. How should I do this job differently, to: (a) Make the physical task easier, (b) Take less time. Today, the task took just a little over two hours, about the same as previous years. Any suggestions?