One thing to keep in mind here is that a simple textile item like a cotton/poly blend t-shirt isn't much more energy intensive than many other items which are commonly disposed of after single use. Since price is a reasonable proxy for energy intensity, throwing away a $5 t-shirt likely isn't any worse than using $5 worth of toilet paper.
Anyways, I hate to appear immodest, but I might suggest that only those of us who have successfully dated a septugenarian can claim true mastery of this realm.