You can have as many IRA’s as you want, but for tax purposes, you can only contribute X amount for the whole year or you can lose out on some deductions. It is best to ask your CPA or tax preparer how much that is.
The only real benefit of having different IRA’s is if the company that you have your IRA with might not be able to offer you all the investments that your IRA is involved with.
In most cases, you might want to consolidate your IRA’s into 1 or 2 since you can decide to small degree which funds you want to be involved in.
For the easy way out, most allow you to decide on conservative, agressive and risky. Most of the time that will depend on your age and what your short and long term goals are.
I would strongly suggest that you look at what the fees are for each of the funds or fr the whole IRA. Also look for any hidden cost associated with trading within the funds for the brokerage firm managing the IRA.