Hello all. I usually change my snowblower oil every 2 years which is less than 50 hours and the manual says atleast once a year. I do live in snowy Buffalo NY and I'm not sure if I changed it in the end of 2013 or if I did it at the end of 2012 because I did'nt write it down. So since I have M1 5W30EP and it's 60 degrees out today, I'm going to winterize the mower and weed whacker and change the oil in the blower. My question is with the EP would you change it every two years based on my schedule or would you extend it? I change the oil in the weed whacker and mower on the even years but they use conventional and single grade. All of my equipment is 4 cycle if anyone was wondering. Thanks in advance, Steve.