There’s a place by me that buys used buses, retrofits them, and resells them. Used to be their main customer was China. They also do service work on them. I take our RV there for the obvious reasons of them having the tools to handle, and was chatting with the service manager one day. He said NEVER buy a used bus, unless you have a ton of money to throw at potential problems. He said that by the time they are retired, they require EXTENSIVE rebuilding of mechanical components, that most places take them right to the limit before retiring.