I stick with only top tier fuel which means Exxon/Mobil, Shell, BP, or Costco around me. While premium could be a waste of money, running 89 octane could have merits depending on your particular operating conditions along with the factory ECM calibrations. Some companies like Ford, Porsche, and others utilize a strategy that constantly looks for higher octane fuel by utilizing the knock sensors. In fact I currently run my old Focus on 89 octane because it really likes it a lot better. There is no difference at the top end, but there is noticeable increases at the low and midrange. Others simply tune their vehicles straight up for 87 octane. I bring this up because I have no clue how Toyota does things. However 89 octane could be useful if you have a fully loaded car and plan on climbing steep grades on a very hot and dry day.