there are 2 ways to prorate some expenses. 1) general - number of days rented at fair rental divided by the total number of days the property is occupied prop reg 1.280A-3 2) tax court method upheld this method (Bolton, 51 AFTR 2d 83-305 9th Cir. 1982) mortgage interest and taxes were allocated based on the number of days in the year. Expenses directly attributable to occupancy were allocated based on the number of days of occupancy
