Generally, you should choose an allocation that makes sense for your situation. There are many ways you can choose to invest, but there is no definite answer.

General rules focus on diversification of assets and strategies that change with age.

Many brokerage companies will have questionnaires and model portfolios that can point you in the right direction. The principles you use to invest your IRA assets are no different from principles you use for any other investments: time horizon, risk tolerance, and your intentional use of the money will all help you arrive at strategies that will be appropriate for you.

It is good to have the guidance of a professional, but it is quite possible to do well on your own if you keep yourself disciplined and informed.