I consider myself a 4b because it is the category that most closely APPROXIMATES my hair. It is just a shortcut, a quick, easily referenced why to describe my hair. Instead of saying "very curly, very coily, very fine, very dense, super thick, super nappy in the middle, looser curl on the sides, more nappy in the back", etc., I just say 4b and move on. IMO, hair typing is not a hard rule, but rather a TOOL, a guide, a rough estimation. Like any tool (or rule for that matter) I discard and use when reasonable, no big deal . . .
There is no real way to exactly categorize a head of hair, especially for people of African descent, it's just impossible (one look at my immediate family, mom, dad and siblings makes that abundantly clear!) and I, at least, use the 4b category to identify my hair as a general guideline to help others (and myself) understand my texture in general. I understand those who choose not to be "limited" by a hair type, but I understand and agree with those who use the system as a shortcut way to to describe their hair. Again, no big deal either way.
I personally find it helpful for someone to give a "hair type" when recommending products as I pay close attention to what other self-identified 4s have to say than say a 2; in the same way I pay close attention to what relaxed heads recommend since I'm relaxed. But I've pickup up great techniques, products recs and other tips from everyone, naturals, relaxed and 1s thru 4s.
I spend a lot of time on
www.longhaircommunity.com which is predominately caucasians and I get great air-drying, deep conditioning and protective styleing tips and products from there as well. The determining factor for me regarding technique is, does it make sense FOR ME? The determining factor for products is, what are the INGREDIENTS? Regardless of who's recommending, if a product is loaded with 'cones, I won't touch it and if a technique doesn't seem practical for me --say one that requires a lot of manipulation - I move on.
I know this tread isn't SUPPOSED to be about hair type, but when the title highlights the word NAPPY, then hair type naturally becomes part of the discussion because "nappy" may cover a lot of heads, from 2s to 4s, depending . . .