They are pretty much essential, but you may want to ditch your mobile phone for ever after reading this.
The average handset carries 18 times more potentially harmful germs than a flush handle in a men's toilet, tests have revealed.
An analysis of handsets found almost a quarter were so dirty that they had up to ten times an acceptable level of TVC bacteria.
One of the phones in the test had such high levels of bacteria it could have given its owner a serious stomach upset.
While TVC is not immediately harmful, elevated levels indicate poor personal hygiene and act as a breeding ground for other bugs.
The findings from a sample of 30 phones by Which? magazine suggest 14.7 million of the 63 million mobiles in use in the UK today could be potential health hazards.
Hygiene expert Jim Francis, who carried out the tests, said: 'The levels of potentially harmful bacteria on one mobile were off the scale. That phone needs sterilising.'
The most unhygienic phone had more than ten times the acceptable level of TVC and seven were above the threshold.
This worst handset also had 39 times the safe level of enterobacteria, a group of bacteria that live in the lower intestines of humans and animals and include bugs such as Salmonella.
It boasted 170 times the acceptable level of faecal coliforms, which are associated with human waste.
Other bacteria including food poisoning bugs e.coli and staphylococcus aureus were found on the phones but at safe levels.
Which? researcher Ceri Stanaway said: 'Most phones didn't have any immediately harmful bacteria that would make you sick straight away but they were grubbier than they could be.