All rides count. Seriously, most of my weekday and some weekend rides are like 15-20 miles.
Friday I rode 16 miles, including a stop to hit up the LBS for a donation of 2 helmets for one of my clients. Yeah, they did it with a smile (it got back to me that someone there read what I wrote here about my bad fitting experience and they figured out who the actual writer was ). I did the loop around Hanscom AFB, which I don't do too often. Yesterday DH and I rode about 20 miles, just around Concord, Carlisle, and Bedford. I couldn't go out until 3:00 and it felt hotter than hell, although it was only 84. What started out as a slow ride, on purpose, became a faster ride, with me hitting a pb on the hill going up by Sleepy Hollow Cemetery (16 mph). It's just a little hill, but I used to have to use my granny gear on this hill.
Today we are driving up to the north shore and going on a beach ride, with a swim stop.