I beleive the question was if shorter drop links would be needed not how long the shocks would last. But people do like to do that sort of thing.
As far as I know shorter drop links are recommended for drops over 50mm though not always nessacary depending on model. My personal thing would be suck it and see.
For the record though I am running -45mm springs and after 10k my original 42k shocks have just flown through an MOT and are doing fine!