People's email habits could be making their accounts a "treasure trove" for cyber criminals, experts are warning.
Over half of those who have sent their bank or credit card details over email still have the information sitting in their sent items folder - potentially making it easier for anyone hacking into their emails to go on to access their savings, research among over 2,000 people has found.
The UK government's Cyber Aware campaign and information services company Experian are urging people to help protect their email accounts by using a strong and separate email password.
More than a quarter (27%) of people reuse their email password for other accounts, rising to 52% of 18 to 25-year-olds, the research found.
Over three-quarters (79%) of those surveyed share personal information, such as their address or bank details over email, and of those who did, two-thirds (67%) have not deleted all the items.
Some 52% of those sending bank or credit card details have not deleted this information.
Two-thirds (66%) of those sending mortgage or tenancy agreements still have these details in their email.
Detective Inspector Mick Dodge, national cyber protect co-ordinator with the City of London Police said: "Your email account is really a treasure trove of information that hackers won't hesitate to exploit.
"You wouldn't leave your door open for a burglar, so why give criminals an open invitation to your personal information?
"Making one simple reset to have a strong and separate email password can make a big difference and help protect you from being the latest victim of cyber crime."
James Jones, head of consumer affairs at Experian said: "Identity theft continues to grow and leaves victims feeling worried and vulnerable.
"We helped around 15,000 victims restore their credit ratings last year, which for complex cases can take several months.
"Having a strong and separate password for your email is one simple but crucial step to staying safe."