In the terms of your FICO score your credit history refers to the how long you have had credit.
 The weight it carries in the FICO score calculation is 15%.
 The weight is carries is due the relation the longer a person has used credit the less risk they represent.
 There are two different factors considered in regards to your credit history.
  The first is the average age of all your accounts.
 You can find this on your own and to do so all you will need is a copy of your credit report.
 In the section dedicated to your accounts in your credit report, you will find when each account was open.
 Just do the math to figure out how many years it has been and average all the accounts.
 The second is the age of your oldest account.
 If you don't know which account is your oldest, you will want to follow the process from above but instead look for the account that was opened first.
  A common mistake many people will make is they do not know this information before they decide to close an account.
 If you close the account that is the oldest you will be hurting both factors.
 Another is to apply for credit if you don't need it.
 Today, consumers are faced with a new credit card offer almost every time they purchase at a major retail chain.
 Applying for all these accounts will also drag down your average age.
    There is little you can do to improve this section of the FICO score formula besides avoid the common mistakes above.
 Also, if you do not carry a balance on your oldest account you might want to use it from time to time.
 Certain accounts sometimes close accounts due to inactivity.
 This method will protect this account from being closed and protect your credit history.