Ive always thought...how do they last so long ? (planes, helicopters etc)
The truth is (i assume) that as long as you've a stong airframe to fit everything to, the rest of the plane bears no resemblance (barring a passing one) to the same plane 30/40/50 years ago.
Its the advances in avionics, propulsion systems etc that keep them in the air for so long. I'll bet if you compare a first generation Tornado (or any other early aircraft), the new ones will be faster, more efficient, more...everything.