Depending upon how often you need a vehicle and tolerance level a car share scheme like Zipcar or Enterprise *may* be worth a look instead of a full on rental.

Say this because both schemes have rather more inclusive insurance built into their rates. IIRC for instance Enterprise caps damage liability at $500.

The downfalls of using a car share scheme for business/important trips is jus that; it is a "share" not always a guaranteed rental. That is if the vehicle isn't where it is supposed to be when your rental starts often you can be out of luck. Ditto if the thing isn't clean and in good repair with a decent amount of fuel.

Thing about car share is that it is 24/7. So if you need to be somewhere at say 8AM you can pick up the vehicle at 6AM and be on your way. Most rental places have set counter hours (outside of airports that is), and thus often you must take a vehicle the day before if you plan to hit road early next.

Final downside is driving a moving advertisement for whatever car share company. Both Zipcar and Enterprise have their respective brand names blazed across their vehicles. One thing I liked about Hertz 24/7 is they didn't which was fine with me.