One of the parts of the annual vaccine does last two years, but the other part only lasts one year, which is why they are both done annually. Mine have never had a full course while being with me (we dont know if they were done as youngsters though), my vet is happy to just start at boosters with their age, and they are only done because i foster, Molly doesn't even bother coming downstairs, never mind go out, and Zi looked interested looking out the window last night, so popped her in front of the open door and she shot back upstairs!! I refuse to vaccinate against FeLV though, and am sure they dont need it at their age.