I have 6 IRAs and my wife has 4. They are all with the same company, USAA, but one is a brokerage account, some are annuities and the rest are Roth or Standard IRA's with mutual funds.

The 1 thing you must adhere to is the maximum contribution for a tax year. Contibutions can start on January 1st and continue through April 15th (Tax day) of the following year. If you contibute more than the allowed maximum you will probably end up paying a penalty on your taxes and a few more entries on your tax forms.

If the max allowed for you based on earnings and age is $4,000, you can split that amount between any number of accounts but when added up, they must not exceed the $4,000.

Depending on the institution holding the IRA's, you will probably have to pay an annual management fee for each account.