The first digit, the thumb, can cause havoc if it roams too far on your personal keypad, warns EDDIE LENNON.

THE advent of the mobile phone has been a blessing for hundreds of thousands of Irish people.

Combining efficiency and ease of communication, it has proved an essential accessory for people who like to stay in touch - so much so that most mobile users find that being without their mobile, even for a few hours, means being technologically naked.

Yet for many mobile users, the pure practicality of having a mobile comes with a nasty sting in the tail.

Most of us spend far more than we would like staying in touch while on the move - and the monthly mobile tally, whether one pays 'as you go' or by bill, often offers a sober and inflated reminder of the financial burden associated with having a mobile. So it pays to treat your cellular companion with a healthy dose of financial caution.

Here are 10 steps to keep a rein in charges.

1. Don't phone outside your network - to other mobile networks or land lines - unless absolutely necessary, or unless your mobile phone package offers a discount deal to do so (which they often don't). This is especially true during peak times, when it can cost you up to 45c a minute. If you want to call a land line, call from another land line.

2. Stop playing text tennis - these days, there's a common assumption that the arrival of text messages has made life easier for mobile users - and has also helped us to save money on our mobile bills. Text messaging is fast, to the point, and neatly avoids all the unnecessary waffle that goes on in the course of many mobile conversations. Or so the theory goes. In reality, the arrival of text messaging has driven many people's mobile bills through the roof. And that can be easily explained, largely by the fragmented communication phenomenon that texting has brought about.  If you're a mobile user who sends a lot of text messages to your friends, it's very likely that the saving money theory simply doesn't hold up - that you're paying through the nose by sending too many texts.  So next time you feel a text message coming on, ask yourself are you texting just out of force of habit. And, if you really have something to communicate, would it not be easier and cheaper to use 'voice' instead of a costly game of text tennis?

3. If you pay by bill, pick the right mobile phone package based on what network your friends are hooked up to - it will save you a fortune on the call you make most often. Sign up for a mobile by first giving a lot of thought to what kind of calls you will make, and when you are likely to make them.

4. When your mobile provider calls you proposing to save you money by signing up to a more expensive package, don't blindly agree to do so when a basic package might be enough.

5. Try not to fall into the habit of calling someone just for the sake of something to do.

6. Don't be lured into buying a mobile solely because the company advertises lots of free call credit. Spontaneity is one thing you need to keep at bay when buying a mobile. So don't be enticed by colourful marketing campaigns that offer you a mobile deal that seems too good to be true. It probably is.

7. Don't buy a prepaid mobile unless you're absolutely certain that it will be cheaper than paying by bill. For most people, it's miles more expensive. It costs up to four times more per minute to make a call than it does from a mobile where you pay by bill.

8. While on holiday, don't answer your mobile - use text instead. The reason is simple: you pay huge 'roaming' costs to receive a call from Ireland.

9. If you pay by bill, review your phone bill fairly often. It's the easiest way to see where most of your money is going. You may decide it worthwhile to change phone provider if it seems that your calls are costing too much.

10. If you pay by bill, make sure to sign up to the 'phone a friend for free' offered by your mobile provider.