On average hair grows at anywhere from five to six inches per year. That’s true whether the hair is on top of your head or inside you nasal cavity. At that rate the average guy will need to insert the nose hair trimmer about every two weeks. To be sure factors such as race, diet and even the amount of water you drink can have an impact on the speed of hair growth. But on average most guys are going to want to go in for a trim every two weeks or so. There’s no law that says you can’t do it every week. But unless the hair is long enough for the trimmer to get a hold of it’s not going to be very effective. So mark it down for every two weeks to start and see how that works.\r