Looking for opinions on lenght of lease terms and PM frequencies for diesel forklifts. Serching for suggestions thanks.

Here is some back ground information.
1. Our location is a hot desert 5 months out of the year 100-120 degrees is not uncommon. The rest of the year is very mild.

2. Currently we use a 4 year lease and purchase extened warranties.

3. All our maintenance is done in house.

4. Our requirement is cabbed units with A/C, heat, F/R fluid and hoses and cab windshield high impact Pyrex 1/2' thick material.

5. Would like to in the future lease machines that are F/R rated with factory not aftermarket cabs.