There are some people who don't do it or advise against it (because dogs certainly don't get these expressed in the wild!). I think if your dog has solid poop they should express themselves... or something like that. I am not very anal-gland savvy (did I just say that? haha

). My info could be totally wrong.
But anyway I get my dog's glands done at the groomers! I don't trust myself with it annd it's not something I really want to be doing myself anyway.