this is totally not scientific but this is how i'm thinking of my hair growth possibilities: i expect to achieve at 2 more length goals after i started taking care of my hair than i had before. in other words, if i managed to get to SL when i treated my hair poorly, I should be able to first make APL, then BSL.
when i was relaxed and treated my hair like trash (in the pool with chlorine that i wouldn't wash out, blow frying my hair, gel, moisturizing only with pink lotion
) i somehow made it in between apl and bsl. now that i'm natural and have recently seen the light i expect that i can reach near waistlength if i want to but certainly MBL.
I know this may not make sense but because breakage was the main culprit in my lack of length retention over the last few years (natural hair ain't having that no moisturizing business) I expected that I should be able to scrape together enough inches per year to add another 12 inches to my hair. since november i've retained 3 inches. Only, 9 more to go!