I used to do this for years, just because I realized it didn’t matter (to me). It drove my colleagues nuts though and they tried to pressure me into “changing my shirt” or making fun of me because I could care less about wearing jeans on Friday. I told them I took a shower once a month whether I needed it or not, so let me be.
Anyway, I no longer do it because I just grew tired of the same look, but I have been considering going back because I found the plain white shirts I used to wear turned out to be very high quality and lasted forever. I can’t seem to find a variety of colored shirts with the same longevity. It seems the mix of cotton/polyester and weave is different depending on the color die, but the white shirts with a 60/40 (cotton/poly) were really a good deal in the long run. Coincidentally, I’m wearing one right now :).