A pillow begins in a stable state, exhibiting full height and even distribution of filling. It rebounds promptly after pressure, maintaining a smooth, elevated surface that supports evenly during rest.
Early changes emerge as faint impressions following periods of use. These subtle dips, primarily in the center, diminish gradually with manual reshaping but hint at reduced resilience.
In subsequent stages, the central area develops a persistent indentation. This low spot endures despite efforts to restore shape, contrasting with the comparatively fuller edges.
Later progression yields a thinner profile overall. The loft decreases markedly in the middle, creating a pronounced uneven contour that persists across the surface.
These observable shifts—from complete recovery to enduring dips and diminished height—mark the pillow's loft as evolving through incremental stages.