, I started dusting not because I believed I'd see anything. It just made sense to me that if you leave a withered end on your head--and no hair is beyond this because all organic matter will grow old and wear away--then like a cancer it'll just cause weakening of more of the strand as the tear travels up or breaks off leaving a weaker end that will just break as fast as my hair grows.
For 30 years, I stayed at SL. Even during jheri curl era which is when my hair really grew long, the longest I ever saw my hair get is 6 inches. People with coarser strands may make it beyond that without trimming. But in time, even their tough strands reach their limit and will break off...even though it may be at a longer length than fine haired ladies.
I keep posting this image coz nothing makes more sense to me than seeing how wearing of strands affects them than seeing it magnified.
Assume you haven't dusted in a long time and then you decide to dust. Dusting means cutting off a tiny bit (say @ C) Look at the damage you leave behind. The third stand is so worn it's thinner than the first/top strand. Why is that? Because it started off looking like the top strand but part of it ripped off. In its skinny state, it doesn't have a prayer. It will take very little manipulation for it to break off. The top strand has a tear which will taper to a thin section on one side and fall off. Leaving a tiny skinny strand.
So after 6 months, the strands endure more wear, and you dust at B. You still leave behind so much damage that continues to rob you of retention.
Now consider if you started off with a good cut to the left of A so that you removed all the already-there damage. Then just before the tears get big, you cut them off right at their beginning. You end up leaving yourself with WHOLE strands that are stronger and that won't be breaking and your retention improves.
When I didn't dust, this is what happened to my strands. They grew long alright:
But they got thinner and thinner at the ends because the damage I showed in the earlier diagram was happening to them. (Bottom pics show how I got rid of the damage I was saying is necessary to get rid of if you hope to retain better) And those thin ends would break off and I'd stay at SL. (I should mention that the length you see of the skinny ended strands was not achieved with me not dusting. Actually until just 4 months before that pic was taken, I was dusting like clockwork every 6-8 weeks. And I went from one inch of natural hair to this first pic in one year following that schedule:
Granted, it's nothing to write home about and even though my strands are thick all the way to the ends, one could argue that my hair is still fairly new so should be retaining well. But I should mention that I never ever saw my hair get to that length in a year. It would take its time and that was my terminal length.
After another year of religious dusting every 6-8 weeks, my hair grew to the longest it had ever been in over 30 years of my life on earth:
Now notice how thick my ends are. And when I dropped the ball on dusting, my hair went to the state below and it took only 4 months for me to get weak strands that clearly were going to break off if I didn't decide to cut them myself:
I started to dust religiously again like clockwork in 2010 and I'm about BSL now and my strands are thick. I don't make a lot of effort to care for my hair so I cannot expect miracles but for someone who is as careless with her hair as I am (not moisturizing, sealing or PSing) that I'm steadily making progress and not feeling stuck when for over 30 years I was, surely is evidence that there's something in regular dusting so you remove tear notches.
I never dust on straightened hair. My hair is in mini twists and I just put them up in a pony and pull one out at a time and snip off the same amount from each one. So you do not need to straighten your hair to dust. Many of us on the forum dust our hair in its shrunken state. By making sure the twists and braids are small, you can get a more or less even results if you take off the same from all of them.