Private employers do not have a legal right to access your personal cell phone in most cases, according to privacy attorneys, but a business cell phone, even when used for personal use, is a different matter.
Using a smartphone provided by your employer can save you nearly $1,000 a year, so it's tempting to do away with a personal phone.
"Most businesses own the equipment and at some point you've signed an agreement to the use of their property and they have access to that property," computer science professor Steve Beaty, of Metro State University in Denver, said. "At some point they can choose to look at your contacts and what you've sent via social media, for example."
He said personal email on your phone is not legally open to employers, however. Law enforcement can access data with a subpoena.
"In general, that's not allowed and is not what many employers want to do," Beaty said.
There's been a significant shift in how employers view mobile data, said Ojas Rege, Chief Strategy Officer for the mobile technology firm MobileIron.
"I see organizations are sensitive to the security of business data but often they don't want to have an access to the personal data on a business device," Rege said. "They don't want to view it and they don't want to delete it. They don't mind it's there."
Five years ago, businesses expected more access to personal data on a business phone, he said.
"Who owns the device is becoming less relevant," Rege said.
In some cases, employers have asked employees to voluntarily provide access to personal data, Beaty said, but that is not common.
Beaty also said to consider how you connect your personal phone to your company network.
Connecting your personal cell phone to your company's WiFi means your employer may be able to view websites you visit.
When it comes to text messages, Beaty says Apple's iMessage and WhatsApp are better options for sending text messages you want to keep private because conversations are encrypted.
"It uses what we call end-to-end encryption," Beaty said.
One of the benefits of that is that when you delete a message from your device, it's gone for good from that device, he said.