None. Need to be prepared to leave at a moments notice. I used to keep a large technical library, but now it is at home. After having seen engineers with 25 years of service walked out the door with zero notice, I will be prepared to do the same.
Someone I know was "walked out" from the UK Ministry of Defence. He wasn't allowed to touch anything after being informed, but he was taken to his desk and asked what was his -- pictures of his children and so on.
(British employment law requires employers to give a notice period, but the employee doesn't have to be at work. This person would have then had three-six months "gardening leave" on full pay.)
