Marian reforms
In the old system each soldier had to supply their own equipment, however with the new large amounts of poorer soldiers due to the other Marian reforms this could not continue to be the case. Marius reformed the system by putting the responsibility of supplying the army in the hands of the general. Roman soldiers also had to carry all of their own supplies, weapons and several days' worth of rations. The century carried with it all the arms and accoutrements required to feed and maintain it. This led to them being nicknamed 'Marius mules.' This logistical change drastically reduced the size of the baggage train required as support and made the army much more mobile. It is possible this was a practice that originated and was abandoned before the Marian reforms. Meaning the Marian reforms simply restored this practice.