in essence, whatever you buy as long as you look after it, should last a long time.
if you thrash them around they will suffer. of course in this case a better built set will last a bit longer.
my tip is to save up and shell out a little more for DC 10-13.4's
get them from
www.marvgolden.com in the states for $370AUD, call it 420 by the time you get it here- as opposed to $500 from Skylines.
generally the more expensive the item, if you get it from the states the more you save compared to here.
dont base your opinion of Altronics on the flying school loaner pairs!
ive got a pair from ebay and they do the job quite well... no match for the 10-13.4 though, love em!