Separation can serve as a stepping stone to divorce, as a way to decide if you really want a divorce, or as a divorce alternative. A couple's time frame for taking further legal action depends on the goals of each spouse. The law does not limit the months or years a married couple can stay separated before seeking divorce.
Stepping Stone to Divorce
In many states, divorce is a matter of right, and either spouse is entitled to dissolve the marriage. Either you or your spouse can move out and announce that your marriage is over. When this happens, your personal time frame for filing for divorce may be fairly short if you can't establish amicable financial and child custody arrangements.
Some couples separate to test out the divorce waters. If this is your situation, you must set your own time frame for making the big decision. Nothing in the law forbids a couple from informally separating for years, but in the end, you may want to make property division, support and custody decisions official.
Some couples find that a permanent legal separation suits their needs better than a divorce. This can be due to religious beliefs against divorce or financial circumstances, like the need for continuing health insurance coverage. In a legal separation, depending on state law, the court may adjudicate all of the end-of-marriage issues, both financial and familial, just like it does in a divorce.