Logic tells me that I will need at least a few basic lens to get by each day, leaving perhaps the more professional range as a rental option. But a simple calculation should tell you whether an outright purchase becomes a wiser decision.
Yes, you would want it insured as breaking or loosing the rental set may effectively mean an outright purchase! Say, the Nikkor 24-70 F/2.8 AF-S ED. A 7-day insured rental will cost approximately $150 (including two-way shipping). The lens itself at the point of writing cost approximately $1500 on Adorama. Now, these lens are built like a tank and has an estimated shelf life of at least five years. You do the maths...we are talking about 10% of total net worth of the lens value for each 7-day you shoot it with.
Personally, my breaking point would be those Nikkor super telephoto lenses! I would resort to rental when I am on those once-in-a-lifetime trips to the African Safari, Antarctica or planet Mars...apart from them, I would rather buy to own.
Visit some of these setup [here] to check it out.