Simple mistakes when booking your week or two away can cost you dear, so it is worth starting your planning now.

Here are 10 things to avoid if you want to have fun in the sun rather than endure a holiday from hell.

1. LEAVING INSURANCE TOO LATE

Almost one in three holidaymakers do not book their travel insurance until the day before they are due to depart, but this is risky, said Ceri McMillan at Go.Compare Travel Insurance: “Too many think of travel insurance as something that covers problems while you’re away, but cancellation is one of the main reasons people claim on a travel insurance policy.”

For full protection, she recommended booking insurance as soon as you pay for your trip – and do not just go for the cheapest policy.

“A good policy should cover travel disruption, personal liability, lost or stolen baggage, and medical expenses in the case of illness or accident, plus repatriation if needed,” she said.

READ MORE: Passport warning as Britons could be caught out

2. AIRPORT UNREST

Striking air traffic controllers and baggage handlers are always a threat and with unions planning a summer of unrest, it’s the same this year.

A-Plan Insurance divisional director David Parker said to check that your travel policy will cover claims following strike action, IT failures and similar unexpected events.

3. ALL-INCLUSIVE EXTRAS

More than a third of Brits planning trips abroad will go all-inclusive, Post Office research shows. Yet beware of those extras.

Last year, they added almost £700 to the average family’s two-week holiday. Factor them in when doing your sums.

4. HIRE CAR RIP-OFFS

Your car rental deal may have looked good value when you booked, but wait until you get to the rental desk.

That is when the charges pile-up for sat nav, child car seats, a second driver and the dreaded excess waiver insurance.

Without that, you could be liable to pay £1,000 or more if the hire car is stolen or damaged, even if it is not your fault.

Check exactly what you will pay when booking, and save by taking your own extras if you can.

You can buy cheaper car hire excess waiver as a stand-alone policy from insurers such as iCarhireinsurance.com or Worldwide Insure.

5. NOT PAYING BY CREDIT CARD

Booking your holiday or accommodation with your credit card does not just spread the cost, it gives you protection under Section 75 of the Consumer Credit Act.

Credit cards offer buyer protection on purchases between £100 and £30,000, which gives you redress if your travel firm collapses.

6. FAILING TO PACK CAREFULLY

Travel light is the motto these days as paying for extra bags can cost as much as the original flight itself, especially on budget airlines like easyJet, Ryanair and Wizz.

The average cost for one piece of hand luggage per flight is £42.79, rising to £67.06 on easyJet, according to luggage experts Radical Storage.

7. SCAMMERS

Scammers do not take a break for the summer, and will not think twice before stealing your holiday money.

Before booking a holiday online, use the padlock icon to the left of the URL to check the site has a valid security certificate.

Arianna Bago, Proxyrack fraud analyst, said unsolicited promotional emails can appear legitimate, but may include click-through links to fake websites designed to capture bank details.

8. CARD CHARGES

Two thirds of Brits are hit by hidden foreign currency costs when using their debit or credit card abroad, said James Lynn, co-founder of travel card expert Currensea: “ATM withdrawals, foreign transaction fees and airport exchange booth mark-ups are just some of the dangers.”

Beat these by ordering cards with no additional overseas charges, or get your currency online in advance.

9. PAYING IN POUNDS

It is increasingly common for foreign shops and restaurants to ask if you would like to pay in sterling.

It sounds sensible but the vendor sets their own exchange rate and will take a cut for themselves.

It is better to pay in the local currency and let Visa and MasterCard set the exchange rates.

Alastair Douglas, chief executive of TotallyMoney, said: “You’ll shell out more if you pay in pounds.”

10. PASSPORT SHOCK

There is no worse feeling than being turned away at the boarding gate because your passport is close to expiring and no longer valid.

British passport holders travelling to the EU must ensure their passport was issued less than 10 years before the date they enter the country, and is valid for at least three months after the date they plan to leave (six to be on the safe side).

Abta director of communications Graeme Buck said: “Our message is don’t delay, check today.”