Pet Insurance has a lot of fallback just like real insurance does, but at the end of the day, it saves lives. It kills me to say this, but I think slowly pets are becoming more and more unaffordable, and all of our medicine mimics human medicine (including cost.) While I don't think Pet Insurance is fully necessary, I think either Pet Insurance or setting aside your own monthly savings is. Another note that Veterinary Medicine can take any insurance and it is up to the owners to fill out paperwork/communicate with the companies, making it very different from Human Medicine. I personally do not like the stories I've heard of insurance having their hands in the pie so to speak with human medicine, and at the moment, no insurance has affected my medicine.
Breeds:
I see people in the other thread mentioning certain costs as well as the breed; and yes, some of the breeds mentioned have far more health problems than a regular mix, and yes, would raise your insurance fees. If you have a dog that is KNOWN to have genetic issues, because some breeds are riddled with these, then yes, your medical costs go up.
Types:
This is all anecdotal but I've had problems with multiple insurances and can't recommend a single one with full confidence. I've had clients sing praises and others tell me about how they've been screwed. Some of the insurances are very new and do not have knowledge of vet medicine that they should have, and I have had to personally contact them to get the proper coverage for my clients. Not every vet will do that. Overall, I've seen the most luck with ASPCA or Embrace (For purebreds), but again, the best thing you can do is read the fine print.
What to focus on:
Illness. Illness is what gets the most people. Save your own money for preventative care (i.e. a spay at the right age can save a several thousand dollar emergency years later), vaccines, parasite preventatives, and regular checkups. But get the insurance for the extreme illnesses that can rack you up a car payment in a night. That's when you want it, that's when people and their pets are the most emotionally vulnerable.
What happens if I don't have anything saved up or insurance?
Veterinary medicine has little to no payment plans. You have a choice (in my area) of scratch pay (a loan, most places do not accept) and Care Credit (predatory loan with massive interest after a certain amount of time.) Too many fall into these traps.
Final thoughts:
Above all else, if you can take whatever monthly premium the insurance would charge you and save that up yourself for your pet, I think that may still be the best option. Otherwise, get insurance that has good illness coverage and read the fine print. Get it when your pet is young. Legally, pets are objects, and have no personhood, at least in the US. This highly affects policy making and reimbursement. If your pet already has "pre-existing" conditions, i.e. your pet has been written to have a luxating patella (trick kneecap) and you later need a surgery for it, but got insurance after this was diagnosed, they likely will not cover it.
Unrelated thought/rant: AI sucks at vet med rn. Don't listen to it or random forums over your vet. A recent study has found that only 60% of people trust what their vet tells them about their pet (Texas A&M study). If I want to give people the harsh truth, and I rarely do, I tell people the more they don't listen to me, the more money I make. Because I tell them the preventative medicine that costs $200 now and saves you $8k later. You don't know as much as you think you know, and neither do online communities (especially reddit).