Generally speaking, a lot of studio managers I know figure rates using simple formulas as a starting point. This starts by figuring:
1. the gear’s useful life in hours
2. the cost of the gear
3. desired profit margin
Then they do the math (numbers below are samples):
$5,000 gear price
$2,500 50% profit
——————
$7,500 total
2 years useful life – I usually use 1,700 hrs/yr as a rough guide for “actual” working time (6.5 hours per day, 5 days a week, 52 weeks per year). For 2 years this equals 3,400 hours.
$7,500 divided by 3,400 = $2.20/hr. This is what you will need to charge per hour to safely recoup costs and a modest profit on this gear.