My boot on my OMC out drive (400 series) is about 7 years old now, has the muskrat guard on it, still looks new and is still flexible. Boat is trailered most of the time, spends mabee 4 weeks in marinas during different derbys, and is completely covered for winter but not heated storage. How long can I go (safley) before replacing it. Probabaly a couple horror stories would be good for me,