Observations on laundry

Today I did a lot of laundry and I noticed some peculiarities in our laundry which I've had on my radar for awhile. The first peculiarity is that when I'm done doing laundry (and I'm very thorough), Sam has maybe one (or no) pairs of underwear and socks in the clean laundry. The other thing is that Matthew has an inordinate amount of underwear and socks in the clean laundry. I have a few ideas on what is going on. My first idea is that Sam is not changing his underwear at all or very little between launderings (which generally happens every four days or so). The second idea is that Matthew is changing his underwear and socks more frequently than what would generally be considered normal. Another idea is that Sam is changing his underwear, but hiding it somewhere where I'm not finding it on laundry day. Hmmm. Usually his laundry is in plain sight (strewn across his floor), but perhaps he's hiding some of it for some silly reason. Another idea is that Sam is wearing Matthew's underwear which would account for both unusual laundry observations. As of now, I'm not exactly clear on what's going on, although I have a strong inkling it's idea #1 and I need to be a bit more aware of Sam's changing habits.