Most human vaccines do NOT provide protection for life - for example a well-known TV presenter got TB because the BCG he had as a 12-yo doesn't last for life. I had to have a booster when I went to Nepal some years ago, and Nepal and India are hotbeds of strains that are becoming resistant to most antibiotics - not surprising when they (or a faux version) are sold over the counter.
However they are not generally repeated for adults because the diseases they protect against are usually far less serious in adults than in children at least in terms of mortaility, though mumps can be far more serious in adult men than in young boys. Partly because the flu virus is always mutating there is a list of chronic conditions and people with those can get a free flu vaccine every year - I do as I have asthma. The elderly can as well - flu can be a far more serious infection for them than for healthy young adults.
We have a whooping cough epidemic at present in the UK (several babies have died, about 8,000 cases in 2012 against less than 1,000 in 2011) and mid-term pregnant women have been encouraged to get vaccinated so they can hopefully pass some resistance on to their unborn babies.
With rubella everyone midwifes are tested when they start training to see if they need vaccinating. Even if one has rubella (as I and most people my age did) the immunity might not last that long.
In the UK we still vaccinate cats every year and anyone wanting to board or show their cat cannot do so unless the card is up-to-date. Good catteries and all shows check that the basic vaccines are up-to-date - they are not interested in the FeLV vaccine, or in bordatella or any others.
And even if you don't vaccinate every year, the cat should still get a vet-check every year. Mine check mouth, ears, eyes, coat, listen to their heart, palpate the abdomen, and weigh them. The weight is recorded and their computer system will display a graph of weight against date. Actually they may do more but that's what I've seen them doing. If the cat is being friendly they also give them a cuddle.