Stair Carpet.

[Alibobs]

As a child I distinctly remember having the stair carpet "moved" so what was on the riser bit moved up to the tread, I am assuming this was to even out the wear but really can't remember anymore than this.

.I've just vacumned the stairs and the riser bits seem loose in places. (Not dangerously so!) Does the carpet need adjusting . Any carpet fitters reading this, I would be grateful for your advice