FICO FACTS from Billy Alt, President 700 Credit Repair-
Your Credit Mix determines 10% of the FICO score
FICO Scores will consider your mix of credit cards, retail accounts, installment loans, finance company accounts and mortgage loans. It's not necessary to have one of each, and it's not a good idea to open credit accounts you don’t intend to use.
The credit mix usually won’t be a key factor in determining your FICO Scores—but it will be more important if your credit report does not have a lot of other information on which to base a score.