Many of the worksheets in Realty Analytics have a slider bar and year box like the one you see in this example.  Using the slider bar to adjust the year of sale, or alternately just typing in the new year of sale in the cell, will cause the model to recalculate the results.  You can change the year of sale as often as you wish to see the effects of selling in one year vs the other.

 

These "Change Year of Sale" cells are synchronized.  This means that if you change the year of sale on one page, the cell on the other changes.  That way as you work in the model, all of the  years of sale will be the same, all the time.