I've decided that I want a divorce, but is it smart to open my own account before officially serving him papers?
Chapter 7 Bankruptcy Attorney
If you need funds available to support yourself until support is ordered by court, definitely you should take money out of the joint account and put it in your own. If you have income sufficient to support yourself, or sufficient credit available on credit cards in your name only, then it isn't necessary. No matter what you do with funds now, it will not have any effect on how property is ultimately divided. In other words the money you transfer will still be characterized by the court as community property that is half his.
Technically if you choose to move funds, you should do it before you file for divorce, not just before you serve your husband.
This question is intended to be a summary of relevant California law where this attorney is admitted. It is not a complete answer or researched legal opinion. It is the policy of this firm to enter into a written fee agreement with all clients, and this answer does not create an attorney