I'm not terribly involved with grooming at the doggy daycare I work at anymore, when I first started I assisted the very pregnant groomer quite a bit and eventually took over what I could (things that didn't involve any actual grooming skills) when she was put on bedrest. Ever since then I'm pretty hands off except for the occasional hotel dog that needs a bath or a nail trim. None of the other staffers here presently do nail trims except for me and the groomer so if the groomer is o-u-t then it falls to me if I'm around.
We had a particularly bad dog in yesterday for a fullgroom and the groomer needed a second person to help restrain her during the nail trimming. Her nails were terrible! Several were curled under and starting to dig into her feet. COMPLETELY UNACCEPTABLE!
I was too busy restraining to get a picture of this particular dog but I've got a couple of examples from the past year:
This pair of trimmed nails came from a smallbreed dog- this is just the portion we removed- the nails were still pretty long after they were cut (due to the quicks being rather lengthy). You can imagine they were curled under pretty well. One of them had pierced into a pad!
Another example shows how long toenails have a great affect on the dog's ability to walk/stand in general. It causes the toes to remain bent at an angle to try to accommodate the nails. This puts added stress on the bones/joints in the foot and can lead to them walking with a limp or some other awkward gait that will also add stress to the body (not to mention being uncomfortable).
I have seen them so bad that they have curled back into the foot and worked their way into the pads causing bleeding wounds many times- which might I add are also incredibly difficult to cut at that point! This goes without saying that it carries a high risk of infection and severe discomfort for the dog.
If you are uncomfortable trimming your own dog's nails- then PLEASE take it to see your groomer or vet because it's a quick, cheap fix and prevents your dog from some pretty miserable discomfort!
