FJR Top Gun
Join Date: Jan 2013
Location: Millgrove, ON, CA
30k would seem reasonable on non-iridiums, at least in my mind. If you see any performance issue/sudden mpg decrease, then a plug may be breaking down and time to replace then. Catastrophic failure isn't likely, but you could always put a spare new plug in your kit (as we did in the old days when things weren't so reliable, and a definite requirement for 2-strokers).
Keep yer stick on the ice....
2014 FJR1300A - Root Beer, 2008 WR450F, 1983 Magna V65 (for sale)