Whether you are a professional player with 10 rackets in your bag or a club player with 2 or 3 rackets, paring your racquets is something you should be concerned with. Just think about breaking a racket or your strings during an important game and your second racket is not exactly the same as the first one.
When the rackets are produced in the factory, the companies themselves give a tolerance of +/- 7 gr. (tolerance) between rackets. Otherwise a large number of rackets would have to be rejected during the quality control stage resulting in an increase in both production costs and the final price of the product to the consumer. For example, when you buy 3 rackets of the same weight model, eg 300g, your two rackets may have a difference of even 14g, with the result that both the balance and swing weight of the racquet are directly affected.