Which motor mount is the most common to go out first.Looks like the rear one is causing all my problems.Should I replace any others when I replace the rear?

 

Wife took off in it this morning,drove maybe 30 miles total said it had a bad vibration even while stopped in gear.Brought it home and I had her step on brake and rev motor while in gear and it looked like excessive movement to me so i'm thinking a motor mount.I just drove it around for about thirty minutes and I can not get it to vibrate,