Assumption: Surgical repair is necessary after a first or second degree tear to the perineum.

FALSE (up to 8 weeks postpartum)
These studies indicate that between birth and 8 weeks postpartum, there was no difference in pain or complications between women with tears that were surgically repaired and those with tears that were allowed to heal spontaneously.

http://www2.cochrane.org/reviews/en/ab008534.html

My Views:
This is interesting because it would certainly be nice to allow tears to heal on their own.  Unfortunately, there are no long-term studies and one of the studies quoted here did find a difference in how the wound closed so I cannot recommend that tears not be repaired.  However, it is nice to know that it is not absolutely necessary.