Hiring CPA vs. DIY to prepare taxes

[Lauren M.]

I've prepared our taxes for years using software like TurboTax. Our tax situation is pretty standard, but in addition to a W-2 from my husband's employer, we own two small "businesses" - a freelance company and a real estate company (both are sole proprietorships). This year we purchased another investment property. My questions:

1. At what point should we hire a CPA to do our taxes?
2. What are items to make sure I document if I prepare our taxes for 2016? Our lender for the rental property we purchased in 2016 told us there is a big tax deduction for our purchase and gave us a piece of paper that he said our accountant would need. Any other items to make sure to include or watch out for?