Just saw your ( I think) older post regarding negotiating starting vacation. I also did that on a new job. Told them I was not willing to go back and begin earning vacation from the start as they offered, had to have a full two weeks to start, and work it up from there. Not only got the two week vacation level, but the day I started they credited me with 80 hours of paid vacation I could use the first year. I wish I had learned far earlier that this stuff can be negotiated. How timid I was in those early days. Also have negotiated to get to share in profit sharing and 401k plans from day 1 instead of the normal wait period to enroll.
The profit-sharing and 401k things are probably the most critical benefits you will have in your life. Even now, if you don't have a million is assets, beside social security an/or a pension, it's going to be tough. And Social Security, as we know it, will probably be gone shortly anyway. So be a good scout, and get prepared.