Properties of sounds are extractable, “autosegmentalizable”, if they are often found to spread, i.e., assimilate or harmonize. Besides tones, other vowel properties (height, frontness-backness, rounding, tenseness) are like this. Vowel length is not like this. Of consonantal properties place of articulation and voicing/aspiration looks like autosegments, manner properties (vocalicness, stopness, glideness) do not look like autosegments.
Compensatory lengthening provides a strong argument for separating sound properties from timing (i.e., the skeleton).
Reconstructed Proto-Greek *esmi ‘I am’ is eemi in Attic Greek, emmi in Aeolian Greek, illustrating that either of the neighbouring segments may lengthen to compensate for the loss of the coda [s].