There are people who trade based in order book exclusively & promote these so called orderflow trading platforms, even these days. Surely, it's a great deed to learn this interesting, exotic & unusual skill, but the thing is it's completely unnecessary.
The real use cases for DOM aka LOB aka order book aka Level 2 data are mitigating adverse selection, reducing...
4 real, levels can't be re-positioned, but there's a lil detail.
As explained in "Real levels: positioning and clearing", positioned levels can't switch direction, ie once a level was positioned as support it can't become a resistance, once a level was positioned as resistance it can't become a support. A positioned level can only be cleared with time, price or...