Your bank or brokerage may limit how many months of transactions are available online. If your account has a lot of transactions, choose a short time period (such as 90 days). Otherwise, your bank may not be able to download your data. If you don't download your previous transactions as you add the account to Money, you won't be able to add them later.
After the account has been set up in Money, you will be able to change the frequency that the account information is updated.
Note
In order for Money to automatically update your online account information, you must allow Money to remember your accounts' sign-in information.