Dog walking can be a full-time occupation or a side-gig depending on how many clients you have and how much time you're willing to devote to it. A lot of us have taken on dog walking on an informal basis, caring for a friend or neighbor's pets now and then.
It's a gig anyone can take on with no real training or equipment. But, make no mistake: If you're running it like a business, you need to treat it like a business, and that means investing in business insurance.
If we can be blunt, there's simply too much that can go wrong. For instance:
A dog runs into traffic and winds up in the vet with a broken leg
A dog gets into a fight with another dog
A dog eats something it shouldn't and requires expensive surgery or medication
Walking your uncle's terrier when he goes on vacation once a year doesn't invite a whole lot of risk. Chances are that your uncle will cover any expenses that occur as a result of your doing him a favor. However, when you're walking dogs for dozens of clients, most of which are not personal friends or family members, you're multiplying the risk involved, for both your clients and yourself.
Many clients simply won't hire a dog walker who does not carry insurance and will subject you to the same screening process as they would any contractor. So, not only should you carry business insurance for walking dogs, you should also look into getting bonded, which will protect you from certain financial risks. Bonding will also send a clear message to potential clients that you can be trusted.
The "gig economy" means that we're seeing whole industries growing around jobs that, in previous generations, might have been considered simple informal trades. A job that used to be something you would do now and then for friends and family has now become a fulltime occupation. Therefore, you need to treat it like a fulltime occupation.
You might not need to worry about getting bonded and insured for the occasional dog-sitting job, but when you've turned that into a business, you need to protect it like a business.