I was wondering how often do you vaccinate your indoor cats? My cats were all vaccinated twice as kittens with the combo shot for calicivirus, parvovirus and rhinovirus. In Croatia we are not obligated to vaccinate at all our cats. But I do it since Picard had calicivirus when he was adopted. I do not want to over do it but I do want for them to be safe. The vets say that you should vaccinate your cats every 13 months. I have read somewhere that it last up to 3 years. Does anybody have any other information? Thanks