The $20 bill is the most common bill in circulation in the United States. It was first introduced in 1862 and has undergone several redesigns since then. The most recent redesign was in 2004, when security features were added to help prevent counterfeiting. Despite these security features, there are some disadvantages to using cash. For one, it can be easy to lose track of how much money you have if it's all in one place. Additionally, a cashless society could be susceptible to hacking and other forms of cybercrime.