Another key point though- is that all of the hairs on your head are not in the same phase at the same time. Other wise we'd go completely bald, eyebrowless, lashless, and "brazilian" when we reached the end phase.
Then we'd have to start back over every 5-7 years! This is why I partly agree/partly disagree with the idea of an overall terminal length as a collective term. The length that each strand will grow to is not *pre-set* as is kind of implied by the term "terminal". What
is pre-set is the length of the
growth phase. Also, some strands will not be at end phase when others are- and those strands that are not, may continue to grow well past the length that the shed hairs made it to before they fell out.
Not to mention, with proper hair care and good circulation some strands may grow to a longer length (within the same period of time) than the others which may fall out more quickly. For example lets say during the anagen phase of one strand I slacked on my regimen- and that strand only grew to a certain length. I may have at some point gotten my stuff together during the anagen of another strand. So strand b will have grown longer than strand a did- though both had the same length of anagen phases. Don't know if that made a lick of sense.
This explains how we trim our hair in blunt cuts and yet a few months later our ends are no longer even (splits aside).
So yes, I agree that there's a terminal length to a certain degree--
but I think what's more important is the length of the growth phase. Terminal length just happens to be the length the hair got to before the growth phase ended. But as is highly proven by LHCF you can maximize your growth phase- and make the most of that time- using various techniques.
I guess my point is just that the main factor is that of the
length of the phase- not the hair. The former is relatively fixed, but the latter is not pre-set.