A wave of new — and, often, younger — owners have helped the community dramatically expand, intensify and diversify.

Marian Rivman is pushing 80. Harriet Luria is a proud 83. In this trio, Carol Leister is the baby at 62. Together, they have decades of experience with yoga.

Most pet parents will spare no penny taking care of a pet, but those pennies can really stack up — especially when medical ...