Before I had DC, I knew that obviously DC would be ill at times but I genuinely didn't realise how much of their time they would spend in illness. I have one at school and one at nursery. Their noses seem to run for 6-7 months at a time virtually constantly from September to when the weather starts to get warmer. Colds, chest infections, conjunctivitis, diarrhoea, vomiting, molluscum contagiousm, chicken pox, coughs which last for a month a time - it just doesn't seem to end 
Everyone says it will get better when they get older. The annoying thing is I end up catching quite a few of the illnesses too