I ran across this when using the trigger to create an event.  When others added workflows and triggers that also did updates, I found the trigger was executed multiple times, causing redundant activities.  To avoid this, I created an APEX " public with sharing" class that had static property(s).  One of those properties was a set which each time the trigger was initially updated, the ID of the tiggering object would be placed in the set as a "Lock", removing it from the set after the record was updated.

Here's the class with the static share property:

// @file
// @author Jack D. Pond <jack.pond@dc.gov>
// @ingroup Queue Management
// @licence GNU General Public License 2.0 or later
// @Description Static Class to keep triggers from executing multiple times, creating
//              redundant entries.
//              
//              By adding a shared class, variables can be shared across processes.  This could also be used
//              to disable triggers for batch processing and testing
//              
//              The concept is to put the id of the triggered object into a set when it is first executed,
//              let that act as a "lock", then removing it after all record updates have been completed
//              
//              The trigger should have both before update, after update activated.  If updates exist in workflows, field updates,
//              or other triggers, any change made in there will reinitiate a new trigger.  This creates a "lock" by adding
//              the object Id into the "updatecalled" set of IDs.  The lock is added the first time a change occurs and triggers
//              the class (Trigger.isUpdate), then checked every time it is run to see if the lock already exists(Trigger.isUpdate),
//              then finally removes the lock after all updates have been processed and the record written (trigger.isAfter)
// 
public with sharing class TeamTrackingLogUpdates {
 public static set<ID> updatecalled = new set<id>();
}

Then added to the trigger:

trigger TechResolutionWorkflow on Case (before update, after update) {
    for ( Case c : Trigger.New ) {
        if (Trigger.isAfter) {
            if (!TeamTrackingLogUpdates.updatecalled.Contains(c.Id)) TeamTrackingLogUpdates.updatecalled.remove(c.Id); // Removes lock once updated
        } else if (!TeamTrackingLogUpdates.updatecalled.Contains(c.Id)) { // Checks Lock, executing code only if no lock
            TeamTrackingLogUpdates.updatecalled.Add(c.Id); // Adds Lock
            //
            // Your code here
            //
        }
    }
}