Thank you so much for your quick response!! really appreciate it. 

For my question #1, as you mentioned I am aware that the bank feed feature can download only limited periods and also I can download csv/qbo files from my banks but this way also has limits. ( 18 months or 25 months back depending on the banks).  That was not my question.

My question was more like " How do I determine how far back I want to/should go to start QBO? " rather than how to use the bank feed feature. 

Is there any standards/guidelines to determine it in accounting world? What are the factors to decide how far back to go?   Or can I just pick whatever periods I like? 

For example:  Let's start from the beginning of 2020 because my taxes are already done in 2017, 2018 and 2019.   Is it a good reason to pick 2020?  

Or,  I should go back to 2017 because that's the year when I started my business ?

Please advise.  Thank you in advance!!