Hardware design changes might not occur as frequently as software updates, but they need to be reevaluated to ensure they still represent best practices based on the latest hardware versions and application instructions from the manufacturer.
People in the automation industry understand that the pace of change and improvement on the software side of the business is relentless. The fact that the latest version of software issued yesterday may be obsolete in a week is just the nature of the industry. What many engineers and designers fail to recognize is that hardware design best practices also change, although at a slower pace than software.
Inputs are nice to look at, but if you're not turning on outputs, you're not doing anything.
A control system is only as good as the input/output (I/O) attached to it. The I/O is the pipeline to instrumentation in the field and is how the control system visualizes and manipulates the process.