Even a new vessel need new plumbing to connect it to the vacuum pump (or pumps, sometimes you need one to to go from ambient pressure to low pressure and another to go from low pressure to very low pressure) and the pressure measuring device(s) and also sealing the holes where the wires go (I guess they have some sensor inside the vessel connected to things that are outside). So a brand new vessel means restarting all the seals from zero.
