I am notorious for being immaculate and persnickety. And I have always worn my dress shirts multiple times between launderings. Only in the 3 most horrible months of summer do they get single wearings. In winter, I can re-wear a shirt about four times. I'll touch up wrinkles, a time or two, with the iron.
For health and safety reasons (and to preserve my pricey shirts), I wash and iron my own shirts. It takes 90 minutes (the only time I allow myself to watch tv) to iron a shirt dry, and properly stretch/tension-set the seams. At my billable rate, ironing time could mean bigtime opportunity cost, if I didn't get the maximum number of wearings between launderings.
A colleague who's also (my ethno-social bracket) and I were confessing to each other that we wear shirts several times. I'll always remember the way he summed up the habit of wearing shirts only once as being part of "...the way the (everybody but we and the Presbyterians) squander their money." A dollar here, a dollar there, it all adds up.
I never wear an undershirt, but have no problems with underarm staining (maybe because I overnight presoak, and then soak twice more during my 3-stage laundering). Generally, I do not use aluminum deodorants. For about a decade, I've been using ALVERA aloe-based natural deodorant. It works, odorwise, better than an antiperspirant: and no staining. Any healthfood store will have it.
Do you guys sweat so much because you're so much bigger than me? Or are you wearing suits in heavier weight fabrics? I have to thank Owens, my first clothier, for starting me out with half-lined, tropical-weight suits, from Southwick. I've moved on to Oxxford, Kiton, and Zileri: but still insist on ultra-light fabrics and half-linings. Suits like that are good for all but the coldest weather (and up North, where buildings are kept so deadly-hot in winter, I'd think they were good year-round). A really long cashmere overcoat, and a big scarf (cashmere on one side, print silk on the other) have kept me warm outside in Minneapolis, Montreal, and Missoula, and allowed me to wear tropical weight suits. That's a big edge for me at meetings where everyone else is redfaced from the overheating. Tassel loafers you can slip off under the conference table help, too.
But now to the subject of man-nipples. Miss Manners says that there are certain things that are beneath notice. To phrase it differently, there are things we agree not to see. I think that man-nipples are among those things. So what if they are visible through a voile shirt? We've agreed not to see them. And for anyone who is actually DISTURBED by the thought of seeing them, I'd recommend Uta Ranke-Heinemann's book Eunuchs for the Kingdom of Heaven, which traces the origins of s(ugly word)ual pessimism (and body shame). Uta's a longtime friend of the current Pontiff, and a biblical scholar of the highest order.
Or, as The Bloodhound Gang sings it, "you an' me, baby, we ain't nothin' but mammals...." (you can youtube the song...I just checked). Enough with the body shame!