[Mister Moose]

There are follow-ups to Brent's answer.

If you are paying someone to do the work, it then is a case of the cost of labor to dress the points vs the cost of new points. At $100/hr shop rate (the rough going rate around here) and stock points costing $15, the mechanic can spend up to 8 minutes dressing the points before new ones are cheaper. Add in the front office push to sell parts and the actuarial warranty expense on using old points, and most garages aren't going to service old points that show any wear.

If you do it yourself and pay yourself nothing, then you can dress the points down to where either the points are so worn you cannot get the proper gap, the metal is all filed away, or the points no longer close in a smooth co-planar fit. My experience is that once any significant pitting sets in the tradeoffs send me to a new set of points.