So my first client ever is picking up his dog tomorrow. I live on the 3rd floor. When he comes to pick up his dog, do I bring the dog downstairs with his toys and bed? Or do I invite the client upstairs?
That's up to you. I don't do curb service but all you have to do is bring the dog down to the building's front door, which is fairly equivalent to someone coming to my house's front door. My customers nearly always step inside so I can give them their pet's belongings and have a short word about the stay. But going downstairs with their stuff seems fine and I would think many people wouldn't want to climb the three flights to just pick up their dog.
Ask the customer which they would prefer? Make the offer.
When the pick up time is near, I take their dog on a long walk so they are not overly excited when the owner arrives. I brush them so they look pampered & tie a triangular piece of inexpensive fabric around their neck to look like a bow or scarf. I then gather all of their pets personal belongings, put it in the bag it was brought in, & set it by the door. Inside I place a thank you note, written on a "dog lover" stationary that says how much I appreciate them trusting me to take care of their furry friend & making them a part of my pack. It's a perfect time to acknowledge good dog behavior & invite good dogs to visit anytime. I also spray bedding w/ linen scented Lysol & wash any blankets or towels they brought as a courtesy so everything smells nice. That way, when its time to leave, I'm standing at the door, ready to help them load up the car & say goodbye. This prevents any awkward moments where owners come in & invite themselves to "stay awhile".