Compatible Dyson DC04 tool set includes crevice, stair and brush tool

When would this part need replacing?
When the tools are split/broken
When the tools are missing

Will fit all DC04 models including:
Fits the following models:
DC04 standard, DC04 Absolute, DC04 Absolute Purple Lime, DC04 Brush control, DC04 De Stijl, DC04 Limited Edition, DC04 silver/lime, DC04 independent silver/blue, DC)4 Zorbster.

Compatible Dyson DC04 tool kit TLS197