Which of these is NOT a characteristic of maintainability in software design?

Maintainability in software design refers to how easily a software system can be modified to correct faults, improve performance, or adapt to a changed environment. Characteristics that contribute to maintainability include easy readability, which allows developers to quickly understand the code; modularity, which divides the system into separate components that can be developed and maintained independently; and clear documentation, which provides guidance to future developers on how the system operates and how it can be changed.

High performance, while important for the efficiency of the software in terms of speed and resource usage, does not directly contribute to the maintainability aspect. A system can have high performance but may still be difficult to maintain if it's not readable, modular, or well-documented. Thus, high performance is not a characteristic of maintainability in software design.