My suggestions for base times.
Infantry ---------------------------------> 270 days (9 months)
NATO/W.P. Mot/Mech brigades -----------> 365 days
Irregullars -------------------------------> 15 days
Marines brigade --------------------------> 270 days
Marines rgt/bn ---------------------------> 210 days
Airborne brigade --------------------------> 270 days
Air assault brigade ------------------------> 365 days
Light infantry brigade ---------------------> 120 days
Armored brigade --------------------------> 540 days (18 months)
Infantry ---------------------------------> 270 days (9 months)
NATO/W.P. Mot/Mech brigades -----------> 365 days
Irregullars -------------------------------> 15 days
Marines brigade --------------------------> 270 days
Marines rgt/bn ---------------------------> 210 days
Airborne brigade --------------------------> 270 days
Air assault brigade ------------------------> 365 days
Light infantry brigade ---------------------> 120 days
Armored brigade --------------------------> 540 days (18 months)