Proper loading of a dishwasher is the best way to avoid costly repairs of the racks. One nick from a knife blade can give rust a place to start, which causes rack damage and eventually makes the dishwasher less effective.
Knives and any other cutlery with pointed edges should be loaded in the cutlery basket. Kitchen knives, such as steak or butter knives, should be placed with the handles facing up to avoid accidents. Very sharp knives, such as those used in prep work, should be washed by hand because they have the potential to cause the most damage. Dishwashers can also, over time, dull the sharp edges.
If a dishwasher rack does have a small nick or two, it's possible to repair the damage using special vinyl repair paint and replacement tips. First, the rack must be cleaned and the old vinyl and any rust must be stripped off using a rotary tool with a wire brush. Then the vinyl paint is brushed on and allowed to dry.
If a tip needs to be replaced, the old tip must be cut off and any rust or old vinyl stripped. The remaining part of the tip must then be coated with vinyl paint and a new tip applied. The paint will act as an adhesive.