Support lines earn their keep only when you refuse to edit them after the fact. In Foundation Chart Reading we ask students to freeze a level once price has tested it twice with visible reaction — a bounce, a long lower wick, or a surge in volume on the defence.
The common habit is subtler: you draw a neat horizontal, watch a break, then quietly shift the line a few cents lower so the story still looks intact. That habit trains the eye to invent structure instead of noticing invalidation.
Try this sequence on a weekly chart of a liquid ASX industrial. Identify the last swing low that produced a higher high. Extend a horizontal from the body close of that low, not from the extreme wick if the wick was thin and untested. Leave the line alone for three full sessions. If price closes through it on rising volume, treat the level as broken and journal the break as a fact, not a drawing error.
Students often ask whether overlapping zones are allowed. Yes — a band of two to three percent can be more honest than a single pixel-perfect line — but write the band rules before the open, not after a surprise gap.