Sport rack? Trad rack? How complete? Aid Rack? Aid rack, and haul gear, and full big-wall everything, including porta-ledge and pig?
What are damage rules? If you damage a piece, you buy it? At a discount if worn? How do you define "damage"? Is a bent wire on a cam enough damage to be damage?
How much does an extra piece of luggage cost? I should be able to get most everything I need into an extra piece of luggage, so any rental that costs me more than that probably isn't worth it. So, if it costs me $100 each way to bring my gear, that means I won't want to pay more than $200 total for rental. So, if I'm doing a serious climbing trip -- a week or more -- I'm not going to want to pay more than $30/day for a week, or $15/day for two weeks.
If I'm on a business trip, and sneaking in a day, or weekend, of climbing -- this might be more helpful. But, then, hopefully I'm hooking up with someone local to climb, and they have gear.