One of common circumstances in everyone’s life and in higher level, in business and industrial activities is lease process. A lease process consists of a lessor, a lessee and the equipment which is being leased. These three elements linked to each other through a lease contract. The lease contract includes many hints and contents like amount of lease and how to pay this amount, the lease period, etc. One of the most important sections of the lease contract is the maintenance section. The lessor who is in charge for performing the maintenance activities of the leased equipment should reduce the probability of failures by performing preventive activities and rectify failures when they occur. Maintenance activities should be done in specified times and they are costly. Hence the proper planning of these activities is one of lessor’s priorities. In this thesis we try to plan maintenance activities (including time and amount of effectiveness) in a proper manner and consider discount as a trick for reducing costs and attracting customer. For this purpose, a model is developed for anticipating the expected income by considering the probability of failures. Using this model, we could earn the most income in the lease period which is requested by the consumer. So the first aim of this model is finding the most profitable time unit (year, month, day, etc.) in all time units of the lease horizon which is divided to short-term, medium-term and long-term periods. Secondly, we try to give options to the customer by make every time units the most profitable time unit using specific cost items. When the optimal lease period is determined, preventive maintenance items including the time and amount of effectiveness of each action will be determined, too. In order to show efficiency of the model, problems in small, medium and large sizes are designed and solved using MATLAB. Sensitivity analysis of model parameters is also presented.
