I have been a substitute for 5 years, no benefits, no paid time off, only guaranteed 1 day a week. They tell you it is best if you get a second job but, if they call you, you have to report to the Post Office and call off at your other job. I may end up being lucky and get full time by this time next year, but most people end up being a sub for around 12 years. The wear and tear on your vehicle is atrocious, I replace brake pads every couple months, ball joints, rotors, wheel bearings, shocks and struts at least once a year. Not worth it. The routes are evaluated, which means if it's an 8 hour route, you get paid 8 hours, even if you work 12, which will happen around Christmas time alot. The routes are actually so under evaluated it is impossible to run under evaluated time safely. You only get paid 10 seconds to deliver a package, and sometimes you have to go half a mile to a house from the mailbox, which that mileage is not evaluated in the route so you don't get paid for it. I would not recommend this job to anyone that actually needs to make money. Maybe someone that just wants a little extra cash, but you will just be using it to fix your vehicle. Good Luck.
None until you are full time in 12 years.
Read above, to many to go over again.