It truly depends on the situation. Some conflicts can be resolved quickly others take a great deal of time. Parties in conflict who are actively committed to the process will resolve faster than those who are not.
Individual conflict coaching can be helpful to understand more about the conflict and their response to it. Addressing conflict situations through role plays and "If - then" scenarios will make a significant difference in how the individual handles conflict.
Mediation allows parties to engage with each other and work through issues, coming up with solutions that best fits them. There is not as much control in the outcome when the legal system is involved, and it is generally much more expensive. Legal action should be your last resort.