I've read so much lately about dogs being over-vaccinated esp tiny ones like ours. i was reading that it is a good idea to vaccininate every 3 years instead of 1.. does anyone have any thoughts on this?? does anyone vaccinate every 3 years??? do you notice any health differences?? layla has horrible reactions to vaccines and now i get them spaced out over a week so that she doens't have to deal with everything at once and the idea of only having to do that every 3 years sounds too good to be true. thoughts please