Westies commonly have skin issues that can get expensive and require lifelong treatment.
Beware cheap companies - they are generally less keen to pay out. I'm not going to name and shame on the open forum, but when you see some company claim forms vet's hearts sink.
If you look to change companies beware that ANY pre-existing condition will be excluded. A few days limping as a puppy might mean the arthritis medication is not paid for 10 years later.
You need a lifetime policy, not one that stops paying after a year.
Of course it goes up year on year, the risk of needing to see a vet and getting ongoing treatment rises as the dog ages.
Pet insurance means you can do the best for your little buddy if anything goes wrong. I hope you don't need to ever claim, but if you do you know he can get the best care. That is what you are paying for - piece of mind.