Are you leaving yourself financially exposed ahead of the summer holidays? Here's how to cover up, says Martin Lewis of MoneySavingExpert.com

Every year, for the past few years, someone with cancer or another similarly serious diagnosis, has contacted me via social media with a similar concern.

They ask something akin to: 'I've just been diagnosed, I was due to go on holiday in six weeks, but now need chemo. The airline won't refund my ticket – what are my rights?'

I find these messages both distressing and frustrating. The honest answer is, you usually have no legal rights unless the ticket is flexible.

This is exactly what travel insurance is for. Yet many people leave it until the last minute to buy it.

This defeats half the purpose of the cover – to protect you in case something stops you going away. So get a policy as soon as you book.

And if you're reading this, and have booked, but have no insurance, you're financially naked – cover up now!

Here are a few more of my travel insurance need-to-knows.

Drink and holidays don't mix...

At least when it comes to insurance. If you plan to drink on your holiday, do note if something happens when you're not fully with it, many insurers won't pay out.

And it isn't just a case of taking care of your health – don't take valuables out with you if you drink because if they're nicked (or lost), you're likely to be stumped.

Go away two or more times in a year?

You can get an annual policy from just £9.

In almost every case if you go away two or more times in a year an annual policy is cheaper than single trip, even if one is just a weekend break.

The only exception is if one of those trips needs specialist cover – such as for off-piste skiing.

Who the cheapest insurer is depends on your age, yet prices start at £9 for an individual policy for an 18-year-old in Europe, while the cheapest for someone aged 50 travelling worldwide with their family is £39.

There's a wide-range of options, so see my full best-buys at www.mse.me/travelinsurance

If you're looking for single-trip policies, see www.moneysupermarket.com or www.comparethemarket.com

Is your EHIC still valid?

Over five million are out of date.

The free European Health Insurance Card means if you go to a GP or state run hospital within the EU, you are treated like a local.

So if it's free for them, it's free for you. Everyone, including children, travelling to the EU should have one with them.

Check the date on yours to see if it's still valid. And if you need to renew do not Google it: you'll find official-looking shyster sites that'll charge you for 'fast tracking', or some other nonsense.

EHICs are always free. Go direct to www.nhs.uk/NHSEngland/Healthcareabroad/EHIC

Cover for the family

The www.nationwide.co.uk Flexplus bank account costs £10 a month (set to increase to £13 in September with some changes), yet account holders get worldwide family travel insurance for those up to age 74, European breakdown and mobile phone insurance for the whole family.

The cover levels are good too – separately this could cost £600/year. So providing you'd be buying this cover anyway, this can be a bargain.

Over-65s cheap cover is possible

Prices rise heavily as you get older. Though cheap annual policies are still possible especially if you're under 75, I've put a full list at www.mse.me/over65travel

The Nationwide Flexplus account above is also worth considering, and if you're over 75 (with no major pre-existing conditions) you can pay an extra £50 and still be covered by it.

Trial and error helps

If you've had past medical problems, regardless of age, it can be a major barrier to getting cover.

The real key here is to try a lot of different specialist insurers and hope one has underwriters that see you as a lower risk.

I'd start with the two specialist comparison sites www.medicaltravelcompared.co.uk and www.allcleartravel.co.uk, then add in some they miss like www.miatravelinsurance.co.uk, www.staysure.co.uk and www.insurancewith.com

I got a tweet from someone recently who went through this list and managed to cut their initial quote from an unaffordable £2,000, to just a horrid £450.

Martin Lewis is the founder and chair of MoneySavingExpert.com