I've had an LLC for around 15 years, with a couple of business CCs, and have never paid D&B anything.
A lot of the answer may depend on what sort of business credit rating you want to establish. For me, the only thing I really care about is being able to maintain business CCs in good standing. My total business CLs are around $12K, which is fine for my purposes.
For someone else, it might be different. For example, if your business needs a lot of financing to purchase inventory and equipment and so on, then you might want to come at this issue in another way.
No. Most important if you contract with the state or federal government (but only to an extent). For the rest of us it's not worth the hassle. I have yet to be turned down for business credit because of lack on D&B info. In fact it has never been mentioned except by D&B solicitors.
Never, ever in this life time pay DNB for anything
I made an account and corrected/updated my information with them, cost nothing. I don't really need/want their report history or anything like that, I just wanted any potential creditors to see accurate information (changed my legal business name to reflect LLC, changed office address, etc).
FWIW i also did the same with experian's business report thing to make sure info was accurate, they didn't charge to update the information either.
iUpdate is free because the federal government says it has to be. They just don't want you to know that.
Everything else they sell is a scam.
I had to have a Dunn number to get a job with a State Hospital to letter their vehicles but they only needed the number.