No one likes to think that bad things will happen while you're on holiday, but it becomes a reality for lots of travelers every year.

The right travel insurance policy can reduce the impact that injuries, illnesses, delays and lost property have on your precious holiday time. Finding the right travel insurance policy, unfortunately, is not as easy as ticking off the box next to "Do you want travel insurance?" at the travel agent. In fact, that could be the most expensive cover with the least benefits. According to Direct Line insurance, buying your travel insurance through your travel agent could cost you up to five times as much as you'd pay if you take the time to research and buy your own travel insurance policy.

Doing that requires a little knowledge beforehand though. It's important to understand the types of medical situations that are typically covered by a holiday travel plan, and which tricks to watch out for that could leave you without the cover when you need it most. Here's a quick guide to what to watch for when you're comparing holiday travel insurance.

1. Watch the excess.

Excess is the amount that you must pay before your travel insurance kicks in and picks up the remainder of the cost. On the typical travel insurance policy, there's an excess of £50 which is often counted against each incident. A few count an overall excess - they might require that you pay the first £150 of all insurable expenses on the trip no matter how many incidents are involved. This can be a vital difference. If, for instance, you stumble and fall, breaking a leg - and your expensive digital camera, along with your eyeglasses - some insurers may count that as three separate incidents, and charge you an excess for each of them, although they all stemmed from the same incident.

Solution: Consider getting a policy with an overall excess.

2. Watch the cover.

Read through the policy carefully so that you can be sure that the most important items are covered. Many policies don't cover you for the most common losses and injuries while you're on holiday. For instance, nearly all policies exclude injuries that happen while engaging in "winter sports".

Solution: If you're going on a skiing holiday, go over the policy, and if necessary, take out specific "winter sports cover" because it's better to be safe than sorry.

3. Cover your baggage.

Your baggage should be insured for at least £1,500, but keep in mind that many items you commonly carry may not be covered. It's typical for baggage insurance to exclude cover for sunglasses, mobile phones, cameras, watches, baby buggies and other expensive pieces of equipment. It's also typical for insurers to set an upper limit for how much they'll pay toward the loss of any one item. If your upper limit is £75 and you lose your £800 laptop, you'll be out of luck.

Solution: Look at getting separate cover for any expensive items that you plan to take with you.

4. Cover your pre-existing conditions.

If you have pre-existing medical conditions that flare up while you're abroad, you may find yourself responsible for all expenses related to them. Pre-existing conditions are also the most common reason for travel insurers to reject your policy. If you have a condition like angina or high blood pressure, a history of heart problems or diabetes, you might be wise to look into travel cover that takes those conditions into account and will cover you regardless. You may pay a bit extra for the premium and have a higher excess, but the peace of mind will be worth it.