Posted: Wed Mar 7, 2018 9:23pm
I don't think there is an easy answer to your question.
The detail is always in the small print of each company's car hire contract, so it is best to read it carefully before booking.
The car is a lump of metal. It costs what it costs. The money is made on the insurance component of the deal. The rental car desk will always try to up-sell the insurance, as this is where the money is made.
Some rental companies offer low (or zero) excess contracts, but these are more costly than those with high excesses. The excess is taken as an up-front deposit on your credit card at the rental desk.
Some zero excess contracts do not include tyres, scratches on alloy wheels, window glass, loss of keys, undercarriage damage, interior/roof-lining damage, flood damage, etc. Some don't even include break-down recovery.
Some are genuinely zero excess, with no extra costs if the car gets damaged in any way, but these are more costly.
If you choose to buy an excess waiver policy independently of the car hire company, and any sort of damage is incurred, the car rental company will deduct the value they assign to this damage from your up-front deposit. You will have no say in the value they assign to the damage. You will end up paying - your deposit will not be returned.
You will then need to make a claim for the lost deposit against your (independently purchased) excess waiver insurance company. You will be out of pocket for a period of time pending processing of your claim.
I'm afraid there is no free lunch. If you pay less, you accept more risk.
Over the years I have rented cars both ways .... with my own independent policy or paid the rental company. Paying the rental company is the lower risk/least stressful option. I have had 2 incidents in rented cars ... one where someone ran into the back of me and one where I had a puncture. Thankfully, on both occasions, I had the zero excess option.
I have also rented many times with my own policy. I have had the odd little scratch/car park ding, and the rental companies have never charged me. But I scraped an alloy wheel on a kerb once in Germany, and paid handsomely for it.
Others on this forum have been less fortunate, and have felt hard done by when the rental companies spot scratches etc.
Independent excess waiver policies usually cover more than one driver, but all drivers must be named on the rental company contract. This usually an additional cost.
I think it is a case of read the offers in detail, read the excess waiver policy offers in detail, think about the risk and make a choice.
My rule of thumb is ... if just renting for a week or 2, once a year, buy the rental company coverage. If renting for several weeks, or several times over a year, the balance of risk favours the independent excess waiver option.
For completeness ... these comments apply to EU rentals only. Other markets operate differently.