A criminal conviction stays on file forever. After a certain amount of time, many offences are considered to be spent and you may not have to tell an employer unless it is a notifiable occupation, for example a doctor.
(in the US) Unless your offense was committed prior to your 18th birthday, you will always have a criminal record - it does not "go away" after a certain number of years. This actually depends on the country you receive the criminal record in. For wiki.answers.com
Credit Report An eviction will stay on your credit report for seven to 10 years. After that, you can write the credit reporting agency to have it expunged. Criminal Record Because evictions are civil actions, they do not create a criminal record. www.ehow.com
The criminal records of individual arrestees are always on file. If you are referring to records of crimes that they have investigated, it can depend on how old the case is as to whether or not it is stored in a records warehouse. You will have to be wiki.answers.com