Now, for the fun bit!!
Totals - Sam: 46, Dean: 30
Unique Ts: 2
Sweaters/Long-sleeved Ts: 3
Sam and Dean don't always wear all the clothes they own, so the following bar graph also keeps track of how many clothes remain "packed" (that is to say, they were used in the previous season and the next season, but not the current season):
Sam has 1 of his 4 sweaters and 7 of his 33 shirts packed.
Dean has 1 of his 4 henleys and 5 of his 17 shirts.
Which means that during the season, Sam uses 26 shirts in the coarse of 16 episodes, while Dean cycles through 12 shirts in 16 episodes.
I need to do charts for how many shirts are one-offs in each season. But perhaps I'll do that later. Rough count right now: of the 17 Sam-shirts introduced in S3, 6 of them are never seen again. Dean only has 5 shirts introduced in S3 and all of them survive the season. (The one that doesn't survive was introduced in an earlier season.)
Hope you enjoyed that!