In addition to the stress of maintaining your own mail-capable vehicle (depending on the route and office), the hours you are given in particular weeks classify under feast or famine -- that is, you are either working 2 or 3 days a week at 3 or 4 hours a pop, or you're working 6 days a week getting somewhere around 50 to 55 hours in. There hasn't really been an in between in my experience. The downside tied into this is that you are expected to be available to work if they need somebody on short notice, and the schedule changes almost daily. Another downside, coming back to this now that I've written my advice to management, is that promotion to a career position is based solely on seniority, as opposed to aptitude or ethic.