61-3-501. When motor vehicle taxes and fees are due. (1) Motor vehicle registration fees, local option vehicle taxes or fees, fees in lieu of tax, and other fees must be paid on the date of registration or renewal of registration of the motor vehicle.
(2) Motor vehicle registration fees, fees in lieu of tax, and local option taxes or fees imposed under this chapter do not accrue after ownership of the motor vehicle has been transferred to another person.
(3) (a) For purposes of this chapter and except as provided in subsection (3)(b), the age of a motor vehicle is determined by subtracting the manufacturer's designated model year from the current calendar year.
(b) If the purchase year of a motor home precedes the designated model year of the motor home and the motor home is originally titled in Montana, then the purchase year is considered the model year for calculating the age of the motor home.