I chose actual exp for 1st yr and cannot change to mileage. If I purchase a work vehicle in the future do I get to start the process over selecting actual exp vs mileage.

If I chose actual expenses for my work truck in year one am I “stuck” using actual expenses for the life of the business or am I stuck for the life of the vehicle used in the business? What if I ADD another vehicle? Can  I treat vehicle number 2 differently in chosing the method of deduction?