The need for side and rear window replacement isn't as typical as windshield repair or replacement as they simply don't receive the same abuse as the front windshield when driving down the highway. Accidents do happen, however, both on and off the road. Side and rear windows can in some instances be repaired, but you should be aware the nature of most damage to those windows requires a full replacement.
When Repairs Are Feasible
Typically speaking, a repair can be made to a small windshield crack or a chip which is no larger than a dime. Consider that as a rule of thumb rather than a law of physics, as every situation has specific considerations as to whether or not a window can be repaired. When road debris is kicked up by a passing car whether you're parked or driving, the damage can usually be repaired. Other situations which can potentially cause repairable damage are strange occurrences which might involve children playing in the driveway or construction work going on in the street.
Why Replacement is Typically Preferable
Because side and rear windows are typically broken as the result of the shock of a traffic accident or someone trying to break into the car, replacements are generally the more common solution. If your car has the safety feature of tempered glass designed to shatter without sharp edges, damaged windows will always have to be replaced. The good news is insurance will often cover this type of damage, so it's always advisable to get an estimate and discuss with your agent whether you want to report the damage and use your insurance or simply pay out of pocket. The final decision will be made according to how it may affect your premium payments and deductible comparative to what you can budget toward the repair which you didn't plan on having.
Differences between Side and Rear Windows and the Windshield
The obvious difference between the front windshield and your side and rear windows is how they were designed according to what they are subjected to during normal driving conditions. The windshield is struck by weather and road debris from other cars while driving, especially at highway speed. When parked, it depends on the car's design and rear window angle as to whether or not it's vulnerable to hail or falling tree limbs. Further, the rear window may be wired for an internal defrost element or built-in antennae, and if the wiring is damaged repairs aren't going to be feasible. Another difference with side windows is the way they are mounted in order to raise and lower instead of being completely glued and sealed into place. These are all considerations which make rear and side windows better candidates for replacement than repair in most circumstances.