life span; life expectancy; lifetime (of a machine)
寿 · 7 strokes
Simplified form of 壽. The top component is a remnant of 老 (old). The origin of the bottom component is unclear.
命 · 8 strokes
Phonosemantic compound. 口 represents the meaning and 令 represents the sound and meaning. Based on the original meaning "command". The meaning later shifted to "fate" and "life".