Trigger for field update in Salesforce

The below Apex code is used to update a field(Comments__c) in Member__c Object,

where Marital__Status and Comments__c are fields n Member__c object.

Code:

trigger commentsUpdate on Member__c (before Insert,before update)
{
     for(Member__c member : Trigger.new) 
     {     
         if(member.Marital_Status__c != '')   
         {     
             member.Comments__c = member.Marital_Status__c;   
         }      
         else  
         {     
             member.Comments__c = 'No comments';   
         }      
     } 
}


trigger.isInsert is true when a new record is created and inserted.

trigger.isUpdate is true when an existing record is modified.