German Army Military Personnel Promotions Discussed

Officers:
German wartime officer ranks were permanent, which often made it impossible for German officers to be promoted to the higher rank which their wartime billet would actually have warranted.
Of course, Adolf Hitler could, and did, force promotions of officers and generals he favored, outside of the normal system.

Enlisted Men:
In wartime, promotions could be made — governed by strict regulations — in the following cases:
a) after serving a certain time (and not dependend on billets authorized in KStN), in particular:

"M" Group billet

"G" Group billet

to
  Oberschütze
  Gefreiter
  Obergefreiter
  Stabsgefreiter
  Unteroffizier
  Unterfeldwebel
  Feldwebel
  Oberfeldwebel
  Oberfeldwebel duty
  Hauptfeldwebel duty
  Stabsfeldwebel

after a minimum of
  6 months
  6 months
  2 years
  5 years
  9 months
  6 years (or 4 years as Unteroffizier)
21 months (or 1 year as Unteroffizier)
24 months (or 1 year as Unteroffizier and 3 months duty as Feldwebel)
21 months (or 1 year as Unteroffizier)
21 months (or 1 year as Unteroffizier)
12 years

    b) into free authorized posts which were regulated by KStN to Unteroffizier, Feldwebel, Oberfeldwebel;
    c) over authorized strength Kapitulanten to Unteroffizier, Offiziersanwärter to Unteroffizier and Feldwebel;
    d) for distinction before the enemy — vor dem Feind — to Gefreiter, Unteroffizier, Feldwebel and Oberfeldwebel;
    e) severely wounded;
    f) leaving active duty — Beurlaubtenstand — to the next higher rank;
    g) killed, in enemy captivity, or missing soldiers.

The usual way of promotion would be Schütze, Gefreiter, Obergefreiter, Unteroffizier, Feldwebel, Oberfeldwebel, Leutnant.

The rank designations Oberschütze, Stabsgefreiter, Unterfeldwebel and Stabsfeldwebel were rewards for long serving soldiers who could not advance further for one reason or another.

See also:
  Military Personnel Billet Groups, Functions, and Ranks Discussed
  Military Personnal Job Descriptions
  Military Individual Figure Symbols