One key element of supply was fresh troops. It is assumed that, in common with other newly-conquered areas, young men would have been recruited into the army (e.g Saddington 2003), although direct evidence is hard to find: epigraphically, there are units of Britons rather than more specifically-named tribes or civitates. It is also possible that sons would follow fathers into the army, so there may have been movement from the vicus into the fort. Again this is based on analogy with other areas, although the tombstone of Nectovelius from Mumrills (RIB I 2142) provides evidence of a Brigantian serving in a nominally Thracian unit.
There has been success in tracing recruitment patterns in the Batavian area of the Rhine delta from the study of seal boxes (indicating letters sent home) and military equipment (from returning veterans; Nicolay 2007). However, such phenomena are not found to any significant extent on Scottish Iron Age sites.