My 16 month old Golden has had his anal gland expressed a few times. The first time the vet suggested it because he kept dragging his butt. The next time he stunk so bad and I had a groomer do it and she said they were full. Well it's been 2 months since the last time it was done and he's dragging his butt quite a bit now although I haven't smelt anything as bad as last time. My question is is this something that will need to be done regularly. Is it ok to have a groomer to this instead of a vet? Groomer charges $15 and Vet charges $43. Thanks!