another oil question

What is everyones opinion on how long oil should stay in a bike before changing it? I only put about 2,000 miles a year on each of my bikes. Can I really go a couple of years between changes or should I change it once a year regardless of how many miles I put on it-

Thanks for the help-

When an engine is running the by-products of combustion create acids and water. If you do not frequently run your engines to full temp for long enough to burn off contaminants, the additive package in the oil will break down and cannot protect the bearings etc from the the acids. If there is no way to operate them frequently, I would consider a schedule to change oil and filters every 90 days or so.I would take the bike for a good ride to get the contaminants into suspension and then change the oil and filter.

Here is a tech bulletin that goes into more detail.

http://www.gulfcoastfilters.com/Quaker%20State.htm