If you get a lease for business property, you recover the cost by amortizing it over the term of the lease. The term of the lease for amortization purposes generally includes all renewal options (and any other period for which you and the lessor reasonably expect the lease to be renewed). However, renewal periods are not included if 75% or more of the cost of acquiring the lease is for the term of the lease remaining on the acquisition date (not including any period for which you may choose to renew, extend, or continue the lease). taxmap/pubs/p535-042.htm#en_us_publink1000208961
Enter your deduction in Part VI of Form 4562 if you are deducting amortization that begins during the current year, or on the appropriate line of your tax return if you are not otherwise required to file Form 4562.