Aspects of the present disclosure are directed to operating time-based circuitry. As may be implemented in connection with one or more embodiments, an apparatus and or method involved detecting timing characteristics of circuitry operating in respective clock domains, each having a semiconductor body region via which a clock signal path traverses. The respective semiconductor body regions are biased at respective bias levels that are based on the detected timing characteristics of the clock signal path that traverses the semiconductor body region being biased.