FYI, if you filter the fluid better, it will last longer and do a better job of keeping the trans and fluid cleaner. Cleaner fluid runs cooler, and you will get more miles out of it. I replaced the big can in my Legacy, (a service fix in the early 90's) with a Magnefine filter, (it goes in the cooler line). I got it at Broncograveyard.com. These filters are used by a lot of the transmission remanufacturers. I'm a big fan of clean fluids!
PS- I also put one in the low pressure line on my power steering.