Accounting treatment

our company reimburses the cost of mobile handset to employees as per their entitlement as per their post once in 3 years. mobile is purchasef by the employees themselves in their own name. Now,whether such expense should be shown as one time exp in company books as employee benefit exp or write off the reimbursed amount in 3 years or capitalize the asset in books of company and provide depreciation on that. What will be the correct accounting treatment of such expenditure. Please suggest