How much exercise does a Tibetan Spaniel need?

As much or as little as you can manage. As a puppy all the normal dog rules apply, you should avoid over-exercising a puppy until they are around 12 months old. But once they are fully grown up, they will just as happy with a 30-minute run around the block or a 5-mile hike. There are some good tips to be found on the Kennel Club website https://www.thekennelclub.org.uk/getting-a-dog-or-puppy/general-advice-about-caring-for-your-new-puppy-or-dog/puppy-and-dog-walking/