I have a 2009 phazer MTX. I had an oil and filter change done before last years season. Due to my job, I was only able to ride about 500 miles. I will be in the same boat this year and will probably only be able to ride another 500 miles. Should I do another oil and filter change? Should I just drain the old oil and replace it with new stuff and leave the filter alone? I've been told that the oil will start to break down after a year even when it is not used frequently. I don't really agree with this and I think that I will be fine not doing an oil change. Any thoughts?