Packing: Build a kit around your trip

Write down how many days you will spend mostly outside, whether you will swim, how much water you will have for washing and how you are travelling. A Cornish coast walk with a B&B each night needs a different kit from four days on a chartered yacht or a wild camp in Pembrokeshire. Check the forecast UV Index for the region in the week before you go.

Sunscreen is the item people most often under-pack. Using the NHS guide of about two tablespoons for full-body coverage in swimwear, and reapplying as your label directs through the day, a family beach week can use several full-size bottles. It is often available at your destination, but prices and choices vary, so packing at least your first few days' worth is sensible. Then fill the remaining space with everything else.

Many airports still apply the familiar limit: containers of 100 ml (3.4 oz) or less in one clear, resealable bag of about one litre. In the US this is the TSA's 3-1-1 rule. Some UK and EU airports have introduced new scanners and changed limits, then reversed them, so check your departure and return airports shortly before flying. Gels, creams, pastes and sprays generally count as liquids; solid sticks and bars are often treated differently. Checked luggage has more space, but put everything in sealed bags.

When you unpack, note what ran out, what you never opened and what leaked. Discard sunscreen that is past its expiry date or has changed in texture or smell. Wash and dry travel bottles. Next time, your list will be shorter and better.