We've been in Portugal for five days now, although I'd hardly know it. Since the twins arrived six months ago, holidays are less and less about discovering the world about us and more and more about observing other vacationing families.

I used to spend hours sitting in sidewalk cafés looking at the locals - how elegantly they smoke a cigarette, how slowly they sip their short coffees, how they swing their hips when they walk. Now I sit by the pool and look at other mothers, hoping to pick up tips.

I've discovered that families fall into two types: the Disposables and the Inflatables. I'm a Disposable - everything I take on holiday can be thrown away, from the bibs to the bottles.

Inflatables are more eco-friendly. There's an Inflatable family staying on our quinta , and they've brought a tiny blow-up paddling pool with them, in which their baby sits under a umbrella by the side of the pool, playing with his inflatable duck. When the baby gets bored, they blow up a ball for him.

It's usually isolating going about as a self-contained tribe, staying in an apartment (because how do you make formula milk in a hotel?) and travelling everywhere by hire car. But there's a joy in being in a country where the waiter whips off your babies to the kitchen to meet the cook. I now know why I love taking my children abroad. We feel welcome.

If you have any experiences of travelling with kids that you would like to share, e-mail: deabirkett@cs.com