People still tend to think they talk a lot on the phone when they actually communicate mostly by email, instant messaging, SMS and Skype, said Craig Lowe, MD of execMobile. "In reality, data accounts for 80% of the cost of roaming."
He said that a WhatsApp message only uses one kilobit of data, but the mobile operators charge in chunks of 25 kilobits, so it actually costs about R3.20c per message. "So sending SMSs from abroad is cheaper, at an average of R2.75 per message."
Working in kilobits is confusing, because users are used to thinking in terms of megabytes, so it helps to know that one megabyte is equivalent to 1000 kilobits, said Lowe. He said that a Skype voice call takes up about one megabyte of data per minute, and a Skype video session takes up to three megabytes per minute.
Other data-hungry activities include the updating of applications, operating system and device software. Some application updates happen automatically in the background when they are open and need to be turned off properly to stop this happening.
"It's important to exit applications and not just quit them," said Lowe. He said that Skype can consume 500 megabytes of data when it is just checking which of a user's contacts are online.
Large attachments can also chew up data while downloading without the recipient being aware of it, said Lowe. "A guy I know got a bill for R760 000 after returning from 11 days in the US due to a video attachment that took days to download because the connection kept timing out."
This person had played in a golf day event just before leaving SA and one of the give-aways was a video analysis of his performance compared with that of a famous golfer, which was emailed to him while he was away.
If the kids are coming along on holiday, there's also the risk of them downloading videos to mum's or dad's iPad or spending hours on Facebook with their friends.
Lowe said that roaming costs vary from country to country and from one operator to another. So before going overseas, travellers would be wise to check roaming rates for the places they are planning to visit. "This includes reading the fine print for hidden costs."
Another tip is to download a data-usage app before leaving and download city guides that can be viewed offline. It's great to keep downloading Google Maps to find directions and to share the holiday with friends on Facebook, but each web page downloaded and updated takes up one megabyte or more of data, said Lowe.
"I know someone who used Google Maps twice and navigated a bit while on holiday in Mozambique and they got a bill for R10 000 when they got back."
Statistics show that 68% of travellers switch off their mobile devices or leave them at home rather than worry about huge roaming bills. But this is increasingly inconvenient in a world that revolves around anytime, anywhere connectivity, said Lowe.
So it's worth looking at the new services that are becoming available that allow users to roam across multiple mobile networks and multiple countries inexpensively at a known cost. One such service works with a small connectivity device to which up to five users can connect with any mobile device and share the data capacity.
Limits on data usage can be set per device for the duration of a trip and live feeds can be sent to users with details of their data usage, depending on the service selected, said Lowe.
He said that using Wi-Fi hot spots is tempting, but has downsides like the fact that it is easy for hackers to steal information from a mobile device if the network is not secure, and quality, availability and cost is often questionable.
For example, it could turn out that the Wi-Fi is only on offer in the public areas of a hotel and not in the rooms or that only the first 30 minutes or so of usage is free.
Another option is to buy local SIMs for each country, but each SIM takes two to 24 hours for the network to activate, and the setting up process can be complex, especially when the instructions are in a foreign language, said Lowe.
