is it a lease or installment purchase? if a lease you can only write off the amounts paid assuming 100% business use. if it is an installment purchase, you can write off the full cost (again assuming 100% business use) using bonus depreciation 168K or section 179 depreciation. I prefer bonus because with 179, you must have business income (before the 179 amount) that exceeds the 179 deduction. also if you dispose of 179 items or business use drops below 50% depreciation must be refigured with 179 being recaptured as income and then you are allowed a deduction using a different depreciation method (but no bonus). with an installment purchase, (really no different than a home mortgage in many respects) you would also need an amortization schedule because it's likely that part of each payment is principal which reduces the balance owed and has no tax effect and interest which would be a business deduction.
