I just finished importing 1099 combined (interest, dividends, capital gains) from Vanguard, Fidelity, TD Ameritrade, and Schwab (to TT Home & Business desktop version.) All went well, although there were two different procedures. Schwab and Fidelity involved logging into the brokerage accounts online while logged into TT online, even though I'm using desktop-based software. Vanguard and TD Ameritrade involved entering numbers into TT for the account and the document ID that can be read off the 1099 forms from those brokerages.
As to volume of trades, I'm a daily trader on Schwab, less frequent trader on Fidelity, and very low volume trader on Vanguard and TD Ameritrade.
As to reviewing the forms, after the import, the dialogue popped up each dividend form for me to review for accuracy. I haven't reviewed the capital gains yet. I don't think it prompted me on those, so I need to go back and review....
