Do your homework. Expect to work very hard (physically). You will be at beck and call to the postmaster and supervisors. Very difficult to make and keep personal plans as you will work upwards to 10 and 12 days strait (easily) before having a day off, even more during the holiday periods. You will earn every penny of your salary. Come to the job with an open mind and willingness to work. Learn to pace yourself early and take your breaks and lunch. You earn them. I came to the position in my 40s and it definitely challenged me to my limits daily. I lost 30 lbs of weight within 12 months.
You will get a paycheck and earn a great respect for postal workers.
Quality of life takes a back seat.