Taking your phone abroad with you is a no-brainer: a text message lets your family know you've arrived safely; an emailed photo of the beach makes your colleagues jealous; and, of course, you can be contacted quickly in an emergency.
The old rip-offs perpetrated by outrageous hotel phone rates can also be avoided if you use your own phone. But although "roaming" – using your phone overseas – sounds relaxed and carefree, it can be costly. The way many people get around this is by taking a laptop and headset, and using Skype.
Whether you're in the centre of Funchal, Madeira (with free Wi-Fi throughout), or at an internet café in Bali, you can talk to anyone else with a Skype connection for free. You can also dial landlines in the UK for only a penny or two per minute, although calls to mobiles are higher.
However, when you are on the move, you'll probably want to use your own mobile. So what do you need to know to make sure phoning home doesn't incur an ET-sized bill?
First, check before you travel that you can use your phone overseas. If your phone isn't activated for roaming, or it is incompatible with the local system, it just won't work. Networks in countries such as Japan work with some handsets but not all – you'll need a 3G handset here, as the frequencies used in the older 2G handsets aren't compatible with those in Japan.
Second, remember that you pay to receive as well as make calls abroad. Calls made in the EU are capped at 36.6p per minute, and 11.5p per minute to receive calls. Check with your network before you go to see if there are roaming bundles to save you money.
Voicemail services can be useful while travelling, but aren't free to retrieve, as they often are in the UK. Also, if you haven't set up voicemail before you go, you may find you can't do it from overseas. Consider asking friends to send you texts instead – they're free to pick up. Alternatively, try HulloMail, a free service for many smartphones which sends your voicemails as emails containing MP3 files ( hullomail.com).
It isn't just calls and texts that cost more abroad. Data, for smartphone users, costs a lot. If in doubt, make sure Data Roaming on your handset is off. If your phone regularly checks email without your knowing, the costs will mount. The EU recently insisted that networks impose a data limit of €50 a month. When you hit this limit you can request for it to be raised.
Orange has launched a new mobile internet browsing bundle for use abroad in the EU. It offers 30MB per day for £3. If you don't use any data, you won't get charged that day, but if you use any at all, then the full fee applies. With T-Mobile you must buy a Euro Internet Booster for internet access. There's a series of boosters ranging from £1 for 3MB to use in a day, to £10 for 50MB to use in a month. Vodafone's Data Traveller offers 25MB a day. It is free on price plans over £40 a month, or £2 a day for cheaper tariffs and pay-as-you-go customers. O2 charges just over £3 per MB, but there's a maximum charge of £40 a month. If your spending hits £40 you can continue to use data until you reach a total of 50MB without extra charges. These rates will be higher outside Europe.
Some smartphones have apps for free voice calls through the internet, though again a Wi-Fi hotspot is needed and not all apps work internationally. Skype is available for iPhone, Android and BlackBerry handsets but to use it outside a Wi-Fi zone varies according to phone and network. Remember that as well as the cost of the Skype call, you'll be using your data allowance. (Skype advises using your laptop in a Wi-Fi area when abroad.)
T-Mobile BlackBerry users can buy unlimited email access for £15.32 a month. If you have an Apple iPhone, iPad or iPod touch, you can use it to make free video calls, called FaceTime, providing both parties are in a wireless hotspot and have compatible Apple equipment.
If you wish to use your mobile as you would at home – to book local restaurants and so on – then consider buying a local SIM card. Pick up a pay-as-you-go card at your destination – typically around €10 – and take an old phone to put it in (check the handset is unlocked to work with any network).
You can buy Spanish or French SIMs from www.0044.co.uk, where you can also opt for a Global SIM card which allows you to receive free calls in 70 countries. It can do this because of the way calls are routed and the type of commercial agreement smaller networks have with international roaming partners.
Finally, remember that using your smartphone as a SatNav works well, but most systems download maps on the go, so data costs can spiral. Nokia and HTC phone users can download maps for free before they travel.
As smartphones work as ebook readers, games consoles, cameras, music players and more, it's often hard to leave them at home. Provided you take care with call and data costs, your smartphone can also be useful on your travels – and save some luggage space, too.
Thanks a bundle
* Vodafone's Passport scheme is free to join and works for 35 countries. You pay 75p to connect each call and the cost is then charged at UK rates – it can even come out of your inclusive monthly minutes. If you receive a call, you pay 75p and the call is free for up to 60 minutes. If you tend to make and receive only short calls in Europe, this will not be to your advantage.
* T-Mobile's Euro Talk and Text Booster costs £5.10 but offers a travel allowance of £7.50 – in other words, you get a 30 per cent discount. Many T-Mobile customers can opt to have one of a range of Boosters included in their monthly tariff.
* Orange has bundles including Euro Traveller. For £5.10 you can make 200 minutes of calls at the rate of 27.4p per minute and receive the same amount of calls free. Pay-as-you-go callers can buy 30 minutes of calls for £5.
* O2's My Europe Extra costs £10.21 and offers a call rate of 25p per minute. It's free to receive calls too, up to a total 1,000 minutes of made and received calls in a month.
* Three has no bundles.