Method for measuring friction in a hair sample, comprising: (a) providing a friction member; (b) drawing it through the hair, generating a frictional noise signal; and (c) capturing the signal by a noise sensor. Device suitable for use in said method, comprising comb means having a plurality of tines and a noise sensor arranged to capture frictional noise generated by passage of comb means through the hair. System for assessing the level of damage in a hair sample, comprising: (a) defining hair categories; (b) associating with each category a standard trace representative of the frictional noise signal generated when a standard sample in that category is subjected to said method; (c) assigning the sample to one of the categories; (d) carrying out said method on the sample; (e) visually displaying the frictional noise signal generated as a trace; (f) and comparing the sample's trace with the standard trace associated with the category.