I have. The reason being that my last dog developped diabetes and costing me over 100 euro a month for the last 5 years of his life. And all the other little alements he got. I was at the vets probably 3-4 times a month.
So when we got Cooper, I got the insurance for him. He had severe panosteitis(growing pains) and we had to see a specialist for him. Xrays, medication... Tons of money spent, just in his first year.
Jinx is also insured, but besides the snake bite(non poisonous, fortunately) she hasn't had any major problems.
The company is called Proteq( the Netherlands)
I pay 20 euro per dog a month. And 19 percent of every vets bill. They reimburse half the price for spaying or neutering. It covers physiotherapie and accupuncture.
I'm very pleased with them. No problems with any of my claims yet.
Some people set up a savings account for the medical bills of their pets. That is a way to go, but I'm not very good at saving money

. So for me, this works just fine!