Remembering a huge number of different passwords is simply impossible for most of us.
But using the same password, for instance, across an email account and an online banking account can leave people terrifyingly vulnerable to hackers.
New research out on Monday revealed the spiralling number of internet accounts is behind a dramatic rise in online fraud.
Fraudsters in the UK illegally traded more than 12 million pieces of personal information online in the first four months of 2012 alone.
Figures from credit checkers Experian says online fraud has increased three fold since 2010, when 9.5 million pieces of information were traded illegally.
Online accounts cover everything from banking to utility bills to social networks, with 25 to 34-year-olds signing up to an average 40 accounts.
The number is set to grow, with nearly one in five people (17%) signing up to six or more new accounts every month.
One in four of the 2,000 people quizzed use a single password for the majority of accounts and one in 20 (four per cent) sticking with the same login details for all their accounts.
Experian says people are putting themselves further at risk by no longer using many of their accounts - meaning passwords are not changed regularly.
Six in 10 adults (66 per cent) admit to having defunct profiles that hold valuable personal and financial information, including social network profiles (26 per cent), email addresses (18 per cent) and shopping accounts (21 per cent)."