What factors should be considered when taking private pilot renter's insurance? I'm just about to start on my first solo and was informed by my CFI that I need to have renter's insurance at a cost of about $180/year.  I looked on AOPA for this insurance and confirmed that the prices is correct if I choose no coverage for "liability for damage to non-owned aircraft".  What are the factors I should consider in making the decision to add/not add this other level of coverage?
Ignoring what you should and should not have in terms of coverage for your self there are some facts to note about getting gap insurance. 

You need to speak with your flight school and ask them what they require you to have as every flight school could be insured differently. For example, when I got my renters insurance I had to have 10K of aircraft damage coverage as the flight schools insurance did not kick in until then. Had anything happened I would have been responsible for the 0-10K worth of damage. In this case you would want coverage for damage to the aircraft. If the flight school has insurance on any and all damage you may not need it on your insurance.