"If parts are not being added back into the design at least 10% of the time, not enough parts are being deleted." I am struggling to understand this one. Is h

"If parts are not being added back into the design at least 10% of the time, not enough parts are being deleted." I am struggling to understand this one. Is he saying that you should remove parts on a routine basis, like a "remove parts/processes" meeting every month and then re-adding them back in once you find they're needed. Or is he saying when you get a list of requirements, remove parts/processes related to those requirements and then re-add them once you find they're needed? Or is it something else entirely?