Veterinary Pet Insurance (VPI) started in 1980; I insured my Labs around 1990 I think and have had continuous coverage on all the dogs ever since. VPI is now Nationwide Pet Insurance; rates went up a bit coverage went down a bit. I think it's still worth having.
It's been the rare year that I didn't get almost all my premiums back. If you have working dogs, it doesn't take much. I was out training on a weekend and the dog went through an old barb wire fence that was in a bunch of weeds. I didn't have any idea there was wire in there. She caught one wire and ripped a tear in her front right armpit. It was pretty bad. Weekend, so Vet Emergency Clinic. ~ $600. That was pretty much all my premiums on her for the year. Vet prices keep going up too. Pretty much like human prices.
If you get the Pet Wellness Plan along with the insurance, it helps out with a lot of expenses too. Heartworm test/meds, office visit, etc. Those covered expenses kind of lower the premium as well, since you have to do most of that stuff anyway.
At one time I had 5 Labs insured; lots of money per year. But every year it was something. One year it was Blastomycosis on one dog. What they paid on that covered probably 60% of the premiums on all 5.
So, yes, I would not be without Pet Insurance on a working dog. YMMV of course.