we don't have one right now, but we have heard comments from others that we should have one running in his nursery at all times to help with his airways. we live on the coast so the air isn't dry like in some areas. it hasn't been an issue so far, he is perfectly fine.. i would possibly go get one if he caught a cold or if he was congested. but is it something that you recommend to be running all the time? have you noticed any difference from using/not using one?