Although it may seem that divorce decisions are always made by judges that are for/against the man/woman, 99% of divorce actions filed are settled prior to trial. Generally, a skilled family law practitioner can advise their clients what a judge would decide if they go to court. Often clients will elect to reach a settlement rather than submit to the added time, expense and emotional upheaval that a divorce trial requires.
The length of time it takes to complete a case depends upon how complicated the financial or custody situation is, the court's calendar, and how quickly the parties can agree to resolve it.
Another tangible is your spouse's attorney. If they are obstructive, uncompromising or bent upon running up the time and costs of litigation, they must be dealt with aggressively. Suggestion is made that despite your other differences, spouses should agree between themselves that any attorney who does not facilitate the orderly progression of their case should be immediately discharged.
Where there is agreement about custody and very little property to be divided, it may take no more than a couple of weeks. Cases of increasing complexity require more time and can take anywhere from six months to a year. The rare court trial that occurs is generally the culmination of two or three years and can cost tens of thousands of dollars.