One in five people with home insurance runs the risk of being underinsured, and that could mean having your claim reduced or even refused.

It can be the same with other types of insurance too, so take 10 minutes to check that you're adequately covered.

Before you begin: Dig out your documents
Gather together details of the insurance cover you already have, such as home contents, buildings, life and income protection, and make a note of the sum insured in each case.

Work out how much it would actually cost to cover your possessions, rebuild your home, and safeguard your family's income in the event of your death.

Step 1: Make a list of your house contents
A typical family home has contents worth around £40,000 (think about all that expensive equipment like computers, hi-fis, and digital TVs). If your contents are worth £40,000 and you only insure for £20,000 then your insurer will only pay half of any claim and may even reject it altogether.

Make a list of everything in your home that you would take with you when you move, from clothes to kitchen appliances.

The best way to do this is to go round each room systematically, list what's there and estimate how much it would cost to replace if you were buying new. Don't forget the loft, garage and shed.

If you have valuable items such as antiques or jewellery, you may need to get a valuation from an expert.

Step 2: Keep up to date
Don't forget that we all tend to accumulate things over a period of time. If you have children, you'll have a whole new range of furniture, gadgets and toys too.

Remember to review the list regularly as you buy new things - five CDs a month can add as much as £800 a year to your contents total.

Step 3: Use a guide
Most insurers have a guide to help you work out how much home contents cover you need. You can usually find these online.

Step 4: Check the rebuild cost of your home
Make sure the sum assured on your buildings insurance is enough to meet the full rebuilding cost of your property (which may be different from the market value). Your mortgage survey may include the cost, or you can pay a surveyor for a cost, or use an online ready reckoner to help you. The Association of British Insurers has one on its website at www.abi.org.uk

Step 5: Don't underestimate
Life insurance is very important if you have dependants. It protects your family and their lifestyle if you die, and yet we are grossly under-insured in the UK.

At the very least you should have enough life insurance to pay off your debts (including your mortgage) and leave your spouse or partner and children with enough to live on. And yet one in four homeowners don't even have enough life cover to pay off the mortgage if the main breadwinner dies.

You should also insure a non-working partner; it costs a fortune to pay someone to run the home and look after the kids.

As a rule of thumb you need a sum that will pay your debts plus (if you can afford the premiums) ten times your gross income.

Step 6: Protect your income
If you're self-employed then income protection insurance (which pays a regular tax-free income if you are unable to work due to sickness or disability) is vital. Critical illness cover (which pays a tax-free lump sum if you're diagnosed with one of a number of serious conditions) is also useful if you can afford both.

Experts recommend you should take out insurance to cover two thirds of your salary, plus critical illness cover equal to your debts including your mortgage.

Step 7: Cover any shortfalls
Now you have a better idea of how much cover you have, and how much you should have, if there's a shortfall then it's time for action.