What to look out for... top ten ploys used by rental firms that drive us to distraction

COVER AGAINST THE INSURANCE EXCESS

At the rental desk there is often a hard sell to persuade you to cover yourself against paying the insurance excess, which can run into thousands of pounds if you have an accident. But you are likely to find better value from an independent insurer through a broker or comparison website.

FULL TANK OF PETROL

If you pay for a full tank of fuel when picking up a car you could be charged as much as double what it costs at the pumps. Also you will only make full use of this if you drop off the vehicle with an empty tank, which most of us find hard to do.

SCRATCHES AND SCUFFS

Take a good look at the car when you pick it up, ensuring any marks are recorded on the hire documents – even if the hire firm appears unconcerned about them. If an office is closed when you return a vehicle take lots of dated photos in case of a dispute later on.

AGE PENALTY

Firms may charge drivers aged 70 or over extra – or not allow them to rent at all. Likewise they may slap on a surcharge for those aged 24 or under and usually hire only to those aged over 21. Brokers can help get an affordable deal.

CLEANING BILL

Muddy boots and sand from the beach are signs of an active holiday. But a car rental company can charge as much as £100 to have it valeted. A brief clear out of major clutter should pre-empt arguments.

CHILD CAR SEAT

The cost of hiring a car seat or booster chair from the car hire firm can boost your bill by £10 a day. Save money by bringing your own. Some airlines let you take seats but check restrictions first.

SATNAV

Arguments over wrong turns can be solved with a satnav, but hire firms charge up to £10 a day for them. Bring your own or use your smartphone, watching out for roaming charges when using it abroad. The trick is to download maps in advance. You do not have to pay for the position-finding function on phones. Or simply buy an old-fashioned paper map.

EXTRA DRIVER FEE

If you want to share the burden of driving do not forget to put your partner’s details into the search engine when seeking the best deal. Having an extra driver on the policy can add £50 to the cost but charges vary between providers.

BREAKING THE SPEED LIMIT

If you break the speed limit or park illegally you will not only be slapped with a traffic penalty, but may face a £50 administration fee from the hire firm, which it claims is the cost of passing your details on to the authorities.

PAYING TOO MUCH

Booking rentals well in advance can slash the cost of hiring. Often there is no cancellation fee. Comparison websites can help you find good deals, as can brokers such as Economy Car Hire.