It's the same test for both the 90 days and the 1 yr NPIP. For the 1 yr all your birds need to be tested, or at least a certain % if you have a lot of birds. Like we usually keep around 40, so all 40 birds needed tested. And you have to agree not to bring in any non NPIP birds or eggs. Keep all your paperwork. That kind of thing.
For the 90 days, it's the exact same test, but it's usually only done on the specific birds you're planning to show or sell. You just test and band those birds.
I don't go test other flocks for other people, just a bird here and there for local kids, but we tested our entire flock twice last year. I was told both times when I submitted my paperwork that all I had to do was ask for my NPIP # and they would give me one because my entire flock had been tested.
I don't feel it's necessary and at least for us there are some things about being NPIP that I don't care for, so I haven't asked for my #. Since I am a tester, it's no big thing for me to just test whenever needed. Usually only once or twice depending on which shows we're going to. If I were having to track down and hire someone else to test every 90 days or even twice a year, well yeah, I'd probably ask for my NPIP#.
HEChicken-Birds in our state as well as every other as far as I know require at least pullorum testing for any birds being shown or publicly sold (think swap/auction) as well as crossing state lines among other things if not for immediate slaughter. Private owner sale to private owner sale, it is not required. Birds bought from hatcheries should be NPIP already and they are supposed to give you a copy of the paperwork when you purchase, if you ask for it. That paperwork covers those birds then for 90 days. Unless you have plans to show or sell birds at a public venue or cross any state lines with them, it really isn't much of an issue.