Upload & Sell: Off
I would have picked 22 lbs, but it does depend on the packaging, which weighs more than some estimate.
Once A item gets to be over about 5 lbs, USPS starts getting expensive. It used to be cheapest. For heavier packages, I use UPS Ground if I can.
My wife worked 10 years for the post office. The young guys drop kicking or throwing packages accross the large room into the hamper was disgusting. At the time, many postmasters were political appointees, or had pull to get the job, qualifications meant nothing. Thats pretty much changed, but there are still some bad apples.
The employees even got together and complained to the head of the region, pretty high up. As far as we could tell, he didn't even investigate.