In either case, the process and techniques used are very similar to those developed prior to the era of motor vehicles. Customers arrange for a meeting time or a delivery time and drop their goods and supplies at the pack station. Packing services are charged by the pound or by the animal, typically with a minimum price depending on the distance from the pack station. Everything is weighed, sorted for each animal, then split 50/50 to get a balanced load on each side of the animal; an unbalanced load will cause the saddle to slide to the heavy side, causing discomfort to the animal, and potentially inviting disaster. The average mule can carry as much as . A mammoth donkey can carry up to and standard donkey limit is . However, most pack station mule loads are limited to