Grooming your dog is not a luxury but a necessity for its optimal overall well being and good health. During the grooming process many conditions like dermatitis, abnormal growths, skin allergies, etc. may be detected and as a groomer I will suggest a prompt visit to the veterinarian to prevent any serious disease.
Certainly you can and I will label it with your name. You can take it back or leave it for the next grooming at the salon.
It could be 2-4 hours depending on:
As soon as possible. You may start to gently brush your dog at home and get him professionally groomed for the first time around 3 or 4 months old. The younger the pup is exposed to the grooming process, the more natural and less stressful it will be.
You can stay but it is not advisable on behalf of the dog. It is too stressful for the pet to see the owner at the distance and it can accidentally get hurt by jumping off the table, pulling on the collar or simply not staying still when being handled by the groomer.
It is better 2 or 3 days in advance or weeks before holidays.
There is no rule on this, since every dog is different. If your dog goes to the beach often or sleeps on your bed for example, he will need more regular grooming than a dog that stays home most of the time with little activity. Usually every 4 to 5 weeks works for most pets.