Rather than try somewhere new, six out of 10 return to the same place time and again, with Tenerife, Paris, Florida, Benidorm and Majorca among the most popular locations, according to insurer LV=.
And perhaps lulled by a sense of security and familiarity, one-third of those going back to a favourite spot don't always take out travel insurance to help them in case of illness, accidents and other catastrophes.
Selwyn Fernandes, managing director of LV= travel insurance, said: "It is easy to let your guard down because you already know the destination, but things can sometimes go wrong."
The under-25s are most likely to leave the UK unprotected - price comparison website Gocompare.com said that half of them travel without cover. Yet, compared to the population as a whole, 18 to 24-year-olds are three times more likely to end up in hospital abroad, twice as likely to suffer lost baggage, and more than twice as likely to try a hazardous activity such as scuba diving, parasailing, bungee jumping or water skiing.
Everyone travelling to a European Union member state, or to Switzerland, Norway, Liechtenstein or Iceland, should have a European Health Insurance Card (EHIC). They give holders access to the same medical treatment as locals if they fall ill or have an accident.
They last five years, but if you already have one, check now that it is still valid, as Gocompare.com said 4.5 million will expire this year. Every person in your group, including children, needs an individual card - without one, they will have no entitlement to care.
Caroline Lloyd, from Gocompare.com travel insurance, said: "You can apply for or renew an EHIC online, and they usually take a week or two to process and be posted to you, so don't leave it until the last minute before you check them."
But be careful - some official-looking websites charge as much as £24.99 to manage applications. It is straightforward, and free, to apply for cards at www.EHIC.org.uk or by calling 0300 330 1350.
However, no matter where in the world you are going, an EHIC should never be seen as a replacement for travel insurance, because of the limits on location and cover.
Despite what more than half of holidaymakers think, having an EHIC does not automatically entitle you to free treatment. State medical provision varies considerably and few countries offer the level available from the NHS.
In France, for example, you may have to pay to see a doctor, although up to 70% of the cost will be reimbursed later, while in Greece, treatment for a sprained ankle can cost £500.
If you need an ambulance abroad, there is no guarantee you will be taken to a state hospital. Many resort hospitals and clinics are privately run and will not accept EHICs, meaning all care has to be paid for. And the card doesn't cover medical repatriation to the UK, which could mean an air ambulance bill of more than £20,000. In the US, meanwhile, it could cost £45,000 to have a broken leg treated and £80,000 for a heart attack.
Lloyd said: "Only travel insurance can give you the assurance that if disaster strikes, you can pay for your treatment wherever you are or be transferred back to a UK hospital if appropriate - £1 million of medical cover should be fine for most situations but some policies offer £5m or more as standard."
Without insurance, cancelled flights, vanishing luggage and disappearing wallets can also leave you badly out of pocket. Look for a policy that will pay at least £3000 for cancellation, £1500 for lost or damaged baggage and £250 of cash cover.
And take additional sports protection if there is any possibility you might try pursuits such as diving or bungee jumping.
Don't take your travel agent's insurance, though - a standalone policy is usually far less expensive. Also, if you go abroad more than once a year, annual cover may be cheaper than multiple single-trip policies.
The quickest and easiest way to find insurance that suits your needs is via a price comparison website.
Lloyd said: "A 23-year-old holidaymaker can find a worldwide, two-week, single trip policy with £10m of medical cover and £1000 of baggage cover from just £17.45."
Even if you are staying in the UK, if you are going camping and can't live without expensive gadgets, take out cover. The simplest way is through your home contents policy. Gocompare.com says it can cost less than £20 a year to add £2500 of cover for items away from home.
But check if your provider will cover items lost or stolen while unattended in a tent, and whether it will pay full value for smartphones. If it won't, consider downgrading temporarily to a budget handset.