Here is an entire military career in one officer's ribbon bars.
Pioneers Oberst Ludwig Arnold Ludolf Meyer (1860-1918) served in higher engineering/fortification/inspectorate staff positions outside of pioneer battalions for most of his 1880-1917 career, before being retired terminally ill.
The top 2 awards bar was worn by him 1903-05. The triple beneath that from 1905-14. The four-bar shows the drawback to the "Old Style" (at the time ONLY style!) ribbons, worn 1914-15 Then the M1915 bar was accumulated by him 1915-16 and worn until his discharge in 1917. The first three bars are stereotypically Prussian and could never have been identified as his if the group had not all come together. But the final WW1 bar allowed for his identification to be re-discovered using award rolls never previously transcribed, and part of our ongoing international publihing efforts since 2008.
Research on such groups often allows for such identifications of completely "anonymous" bars original wearers. These ribbons are, after all, a military life-at-a-glance.