Charge per dog or flat walk rate?

I charge per dog, but offer a discounted rate for multiples. It's definitely more difficult to handle multiple dogs at once; even if they're used to walking together, it's often still a bit chaotic with someone who isn't their owner, and you're handling extra equipment and poop.

I charge half price for the second dog.

Usually, I've charged a flat rate per walk for 1 or 2 dogs. If 3 or 4 dogs, then my rate is more. It's worth mentioning this is for small dogs and with frequent ongoing calendared needs. Another thing (besides frequency) that you might consider is what other professional walking services in your area offer to make sure your rate is still competitive. Note some walks are bonded and insured, which could also impact client decision, especially when comparing rates.

I used to just charge a flat rate, when I was only walking small dogs. But I have a regular client that has 2 Great Pyrenees Mountain Dogs that I walk together every weekday! Of course I charge more, since they are more of a challenge to control, larger poops & I have to use my weight when they go the same direction at the same time! I love them dearly, but there are few walkers that will take them on as clients, since they literally are HUGE! (The first time I met them, the male jumped up on his hind legs & put his front paws on my shoulders!) That client referred me to a neighbor, who just got an 8week old Vizsla puppy!

Each size/age or special needs will have different challenges, so you need to evaluate your time and effort and be flexible in your prices to adjust for the situation.