If you have a dog or a cat that you feel needs to be professionally groomed, I am begging you to investigate the hell out of the groomer that you find. First of all, dogs hate it. No matter what you tell yourself, they hate it. Even the dogs that don't seem to mind hate it. So that is the first issue. Since the day is going to be miserable for Snoopy/Garfield, please find the place that will try their best to make it as comfortable as possible.
The woman who owns the grooming shop that I've been working in is a nice woman, and I do believe she loves animals in that typical animals are beneath me, but I love them kind of way. In that kind of way that pets fill her voids and needs instead of pets being actual viable living creatures who are not here to serve humans. But after working there for a few months now, I have seen some things that quite frankly are not really okay. If you take your furry friend to get groomed, ask them what kind of shampoo they use. Ask to see the bottle. If you worry about harsh chemicals in your own shampoo, do you want your friend to absorb chemicals in their skin? Also, does the groomer allow the animals to roam, or are they in cages. If they are kept in cages, oh I'm sorry, I forgot we call them kennels to make ourselves feel better. Anyway, if they are kept in "kennels" are they taken to go potty at any point, especially for people who drop the dogs off before work, and pick up after work. I don't know about you, but I pee multiple times in an eight hour day, especially when I am scared, and being washed and dried, and groomed, and I'm scared. Which is another point, please try to take your fur friend on a day that you can pick them up in less than eight or nine hours. It makes the whole process a little less traumatic. Especially if it is a cat. Cats in general hate getting wet, and then when they are already feeling so undignified to be in a "kennel" surrounded by yapping dogs is really too much. A little side note about cats, people stop declawing your cats. It is cruel and inhumane. I thought vets had stopped doing that cruel procedure. We humans are such DICKHEADS!
Pressure the groomer about when you can pick up your pet. Washing, drying, and grooming takes an hour tops, unless it is an extreme situation such as fleas, severe matting, etc. So there is no reason that your dog should have to be stuck there for six or seven hours, and if they are truly that busy, make sure it is as pleasant of an experience as possible, or find another groomer. If it is a groomer who has an open play area, obviously that makes the experience more pleasurable. Would you want to be in a "kennel" for eight hours wondering what the hell is going on?
In all honesty, my best advice is to bathe your dog at home. And I just checked there are dog grooming tutorials on YouTube. Or just bathe your dog and don't cut the hair. The first time I saw an ungroomed poodle, I couldn't believe how cute they are when we don't force our aesthetics on them. Anyway, if you don't personally know the groomer, do it yourself. It will save you money, and it will save your fur friends psyche!