When Must Profiles be Maintained? 
Use
Changes in system profiles are infrequent for most productive R/3 Systems. Changes are needed only in exceptional cases. For example, SAP service processes may need to be moved from one instance to another. Changes for non-productive systems can be frequent. In either of these two cases, an easy mechanism for maintaining these changes while establishing a high degree of integrity is important.
See also:
Start Profile: Changing Instance Services Default Profile: Changing Global Instance Parameters Instance Profile: Changing Instance Parameters Basic Maintenance Extended Maintenance Checking Profiles Reference Server of a Profile Profile Versions When is a Profile Change Active? Checking Active Parameters