Mutual consent: six to eighteen months
The structure of a consent divorce is fixed. A joint petition is filed, statements are recorded on the first motion, a statutory period of six months follows, and the second motion is then heard and the decree passed.
Where the court waives the waiting period, permissible where the parties have been separated long enough that reconciliation is genuinely impossible and all issues are settled, the whole matter can conclude in a few months. Where it does not, expect the better part of a year. Delays here come from incomplete settlement terms, a party abroad, or the second motion not being moved promptly.
Contested: measured in years
A contested divorce moves through a defined sequence, and each stage takes as long as it takes.
What actually makes it faster
Settling the issues rather than the question of divorce. Most contested divorces are contested over money, property and children, not over whether the marriage should end. Once those are resolved, the matter usually converts into a consent petition: which is the single most effective way to shorten it.
Beyond that: complete documents at filing, correct addresses so service is not delayed, taking mediation seriously, and not filing satellite proceedings that have no purpose beyond pressure. Every additional case adds dates to the calendar of the main one.