Some cats cough up hairballs and/or throw up their food much more frequently than others, but it's a fact of cat life. Something like that every couple of weeks is well within the range of normal. As far as hairballs are concerned, all you can do is try to get them used to frequent combings and brushings, and try to find a flavor of petromalt that they like. Mine have gone on and off it, sometimes being more than willing to lick a bit off my finger, other times turning their little snooty cat noses up at it.
