The best way to enhance standard SAP R3 functionality without modifying the standard code is with the help of user exits. The user exits in SAP are also sometimes called as customization spots. Such user exits or SAP enhancements use function modules and are called from the standard SAP code.

Earlier, in order to enhance the functionality in the SAP system, mostly "Z" or "Y" programs were used. These were customized programs defined in table T80D for client dependent user exits and in table T80I for client independent user exits. One of the biggest benefits of using user exits is that upgrades do not erase the functionality in the SAP system. This means that the enhancements do not have to be transported or re-entered into the system. However, as a word of caution, enhancements should be throughly tested to ensure that they work as intended.

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