If you're operating a business through a partnership, company or a trust, you must have a separate bank account for that business. 

If you’re operating as a sole trader, you don't have to open a business bank account, but it's better if you do. That way you can easily separate your business transactions from your personal ones, including any cash taken from money your business receives (often referred to as 'drawings'). 

How long to keep banking records 

Banking records need to be kept for 5 years, starting from when you prepared or obtained the records, or when you completed the transactions the records relate to, whichever is later. 

You should keep records long enough to cover the period of review (also known as the amendment period) for an assessment that uses information from the record.