Having used one for over 10 years in an industrial environment, where it was exposed to shocks off the richter scale and clouds of very fine dust, I can vouch for the robustness of the design. Mine was a 15 jewel and the only un-jewelled train pivot hole elongated, stopping the watch, yours being 17 jewel this will not happen to yours. With a clean and oil every 5 years or so the life expectancy of a Seiko 5 must be measured in centuries. It's very much like the terminator, it just will not stop. A very nice find Will.
RogerC