When you think about annual reviews it is easy to think, "I don't have a day to review and preview, Matt. I'm busy." I completely understand that - I'm busy too. What I can say is that if you think about how many work days there are in a year (about 250) - to take literally one day out of your year is not even equivalent to 1% of annual workdays.
When you think about the amount of time that you actually spend out of the year reviewing and previewing or planning so that you can be focused and successful, it has an exponential effect relative to relative to the amount of time that you actually spend on it.
I protect five days each year for reviews and planning. One each quarter and another for the annual review in December. Those five days are equivalent to only 2% of working hours for the year. We see 2% can make an exponential impact on the effectiveness and success of the other 98%. It really is crazy when you think about the time that way, but it's effectively how you are using your time to impact the rest of your year.