It is standard procedure to replace the oil filter at every oil change, especially when you stretch it out that far. Some manufacturers say to replace the filter at every other oil change to make the cost of maintenance falsely appear less expensive than for their competitors. No mechanic would do that. In fact, if you read most owner's manuals, if they do say to replace the filter at every other oil change, it is only for "normal" driving conditions, but it's impossible to meet those driving conditions. If you drive in the city, on the highway, in hot weather, in cold weather, etc, it's considered "severe service". We joke that if you drive too much at night, or in the rain, or make too many right-hand turns, that will fall under severe service.
Also consider that there's a half a quart of old oil in the filter and passages that wont drain out. It's not the oil that wears out. It's the additives in it that become depleted. The reason to get all the old oil out is that carbon, hydrocarbons, and other contaminants are suspended in the oil so it will be transported to the filter. Some of that circulates many times before it gets trapped. If it's still circulating through the filter, you want to get that oil out, otherwise the new oil will start out dirtier than normal right away.
To not change the filter would be like getting all cleaned up for a night on the town, and you put on your finest clothes but wear a moldy old pair of socks. You could, ... But you wouldn't.
Saturday, July 5th, 2014 AT 2:13 AM