At 4mm, your hygienist calls it early gum disease. At 6mm, it's getting serious. At 8mm and above, teeth start to move. They shift. They loosen. In time, they fall out — or they have to be pulled because they can't be saved.
On average, untreated gum disease causes about 0.2mm of bone loss per year. That sounds tiny. But a 4mm pocket only needs to reach 6mm before the conversation moves from 'deep cleaning' to 'we might need to take that tooth out.' That's just ten years. Less if you smoke. Less if you're stressed. Less if your body is run down.
You can't brush your way out of this. You can't floss your way out of it. You can't rinse your way out of it. The only thing that changes where this is heading is clearing out the bacteria below the gum line. Every day. Before it has time to harden.
Every week you leave those pockets alone, the sticky film hardens, the swelling gets worse, and the window to fix things without surgery gets smaller.