If you make a lot of calls, look for a generous allowance, and check if this includes the type of calls you make. If you make a lot of calls to certain numbers not covered (like international numbers), think about buying a special add-on bundle to avoid additional charges.
Make sure you know how much it will cost if you use more than your allowance of calls, texts and data. Some providers charge a lot if you go over your monthly limit.
Remember also that your smartphone might convert a text message from SMS (Short Message Service) to MMS (Multi-Media Service), which can be more expensive. This may happen, for example: If you send long text messages (longer than 160 characters);
If you send a message to lots of people at the same time ;
If you send a text message to an email address;
If you include a subject heading in your text message;
If you send pictures or photos in your text messages;
Or if you use emojis in your text messages (some handsets automatically convert an emoticon like :) into an emoji.
You may be able to turn off the MMS function in your phone's settings.
If you choose a mobile contract rather than a pay-as-you-go (PAYG) product, this means you will be billed for charges above your monthly allowance. With PAYG, you can only spend the credit you have bought. - This gives you more control over what you pay.
If you find yourself regularly using more than your data allowance, speak to your provider about a more suitable one - don't assume they will contact you to discuss a better deal.
If you're nearing the end of your contract, think about changing your tariff or switching provider to get a package that best suits your needs.
If you regularly go over your allowance, check to see if you can change your allowance. Some providers let you do this without charge. If you’re worried about going over your allowance, speak to your provider to ask if you can set a limit on your account, which will stop you spending over a certain amount.
If you choose a deal that offers ‘unlimited’ allowances, check if it comes with a fair-usage policy. If it does, check what the maximum usage is and what happens if you go beyond this - you may be charged or have your usage restricted.
If you can't switch, ask your provider if you can buy extra allowance - such as extra data or calls. If you do this, check when you can start using it and whether it's provided on a one-off or rolling basis.
You can usually monitor your usage from your smartphone by using an app from your provider.
Most providers also offer an online account where you can check what you have used.
Also check your bill for any items you don’t recognise and speak to your provider if you spot any.
Even if some or all parts of your allowance are ‘unlimited’, it’s still worth keeping tabs on your usage, especially if there's a 'fair usage' policy in place.
Your usage can change over time. Check whether you can increase your allowance, ideally before you sign up to the contract
If you let others use your phone, keep an eye on what they do. for example, avoid your child inadvertently racking up large bills from 'in-app' purchases by keeping your handset password private, or setting up a password.
Some devices allow you to turn in-app purchases off altogether. Our video guides offer step-by-step instructions for turning off or password-protecting in-app purchases on some popular handsets.
Always treat your phone as carefully as you would your bank or credit cards.
Take care when using your phone in public, don’t let it out of your possession.
Smartphones can be worth hundreds of pounds and thieves can quickly rack up huge bills on stolen phones.
It is important you contact your provider as soon as possible as you may have to pay for unauthorised calls from your phone before it is reported missing.
If your phone goes missing and you are with Three, Virgin Mobile, Vodafone, EE or O2 for mobile services, you should only be responsible for paying up to a maximum of £100 for any unauthorised usage - if you report your phone as missing within 24 hours.
If you are with Vodafone and you miss the 24 hours but report your phone as missing within five days, you should only be responsible for paying up to £500. See the Government's announcement.
Once you have reported your phone as lost or stolen, your provider can stop calls being made on your account or from using your phone at all. Your provider can also stop anyone else from using your phone by blocking its IMEI. You can get your IMEI number by keying *#06# into your handset. Make a record of this number, as well as the make and model of your handset and keep it somewhere safe.
You can also download an app which can trace your phone if it is lost or stolen and can enable you to wipe details remotely - such as findmyiphone and Android device manager.
Some mobile insurance policies may provide some cover for unauthorised use.
If you do decide to take out mobile phone insurance, you may be obliged to let your insurer know if your phone is lost or stolen within a certain time frame.
Make sure you put a passcode on both your handset and SIM to make it more difficult for thieves to use.
Since 1 October 2018, all mobile providers must give the option to limit the cost of bills to new customers, and to any existing customers who agree to extend their contract or enter into a new contract. We have published some useful FAQs on setting a mobile bill limit.