This is all good to know, but I have a slightly different question.
I understand that my data (23 years of it) will remain 100% intact If I downgrade from H&B+R to Premier. But, what do I give up by downgrading? Is it a loss of biz-related categories on reports? I haven't been able to find anything authoritative on the topic. TIA.
The categories will still be there. And you will be able to use the accounts in non-business related reports and views. What you will lose is the ability to work with the business accounts, A/R, A/P, etc. No new invoices. No new other business transactions. Business views will no longer be available.
There may be other side effects of downgrading. Having never done that myself, I can't say for sure. If you are 100% sure that you will not need to work with business functions any longer, go ahead and try.
If you use the "Buy Quicken" link at the top of this page, you'll find a comparison of those products.