I think the longevity of the original Stock Bosch Nozzles is based on if the OP did the Diesel Purges, kept Valve adjustments and once in a while did the IP Timing.

Normally after one hundred thousand miles the Injector Nozzles are on they way out.

Reusing them or not also is going to depend on how picky the Person doing the Pop Testing is. Way back in the 1970s when I did that sort of thing I rejected a lot of new Bosch Nozzles during the Pop/Nozzle Opening Test.

For sure if you bring the Injecto up to 200 psi below the Pop/opening pressure and it drips too much you need a new Nozzle.

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84 300D, 82 Volvo 244Gl Diesel