If they are happy enough then I don't use it as I think their body should be able to fight off a low-grade to mild fever without too much hassle. I did use it a bit with DS2 last week as he had a cold and was just generally miserable but didn't have a fever, but if his cold was anything like the one I had at the same time, then his little head would have been pounding from the headache like mine was. My DD2 though never had panadol till she was nearly 3 as she would never take it and would either spit it out or vomit it back up, so I spent many a night with a wet flannel on her forehead or tepid baths trying to get high fevers to break.