If you’re just walking down the street it’s weird. If you’re doing physical labor or something and it’s hot, I don’t see a problem. And of course swimming or beach. Or basketball, a lot of the guys do that.
I’m a fairly copious sweater myself, but that’s why I’d never dare run without a tech shirt. At least while moving, the sweat is more troubling when I’ve got nothing to soak it up with. When I stop, it’s a bit different–but there’s no real help until the sweat finally turns off.
My body makes women swoon so much that I’m pretty much restricted to going shirtless only at the beach, and even then I have to register with the local authorities.
In the shower, or when I’m home alone after a shower and don’t feel like getting dressed. That’s it. It doesn’t make you feel any cooler, and no one wants to see my gut.
Plus, not wearing a shirt makes my back itch.
-Swimming (pool, ocean, lake, river)
-The rare times I’ve been in a hot tub.
“I’m too sexy for my shirt. Too sexy for my shirt. So sexy it hurts”
Actually not in public. Too goddamn hairy.
Very rarely, we have had the skin cancer message in the public for 30 or so years. Even when swimming I wear what we call a rashie, UPF50+ etc.
The reason we call them a rashie is we used to wear them when surfing to stop rashes.
I don’t think it is appropriate to be shirt less off the beach or in public.
Never.
Gosh, post after post, thread after thread; consistent, unblemished sunshine. How do you do it? Extra fiber??
The only times I’m shirtless is when showering or occasionally sleeping. My partner goes shirtless a lot; I would too if I had a body like his.
In civilised company, never (unless swimming). Even in my sailing days I had a rash vest on under my life jacket. Part of it is physique, part of it is because I have a foolish commitment to looking classy 
The only time I regularly went shirtless was when I worked as a summer camp lifeguard, where the general practice was “sun’s out, guns out”. I was in and out of the water constantly, so it made sense.
When I was younger - starting in college, I used to LIVE without a shirt in the summer. My preference was to wake in the morning, toss on a pair of shorts, and I was good for the day. Of course, I’d don a shirt for classes, work, stores, etc.
This practice continued through most of my 20s - tho mainly was confined to around the house and while working outside around the house. At some point my wife persuaded me that no one else was especially interested in seein my shirtless torso. So I started wearing sleeveless tees.
These days, shirt comes off as soon as I hit the beach, but that’s about it. On hot days I’d rather keep the shirt off inside the house than turn on the AC. Up until a year or so ago when I used to run, I would take my shirt off on the hottest days. Posted a thread about that some while back, asking what folk thought about shirtless runners.
I’m 52 now. Used to be in pretty good shape, and still consider myself reasonably fit for an older guy.
When I am walking the dog. Which I do every day for an hour or so. I work out a fair amount, so I don’t frighten children, unless children are frightened by fedoras and those big-ass sunglasses that go over my regular glasses, and my cheap sneakers from Wal-Mart.
Regards,
Shodan
Only on the beach, round a pool or in my own garden. And in beach-resorty type places I’d probably be OK with keeping my shirt off to go and buy an ice cream or something close to the beach, but I wouldn’t walk round town with no shirt. It’s just not classy.
Casual Friday. It’s a thing at my office. 
I always mow the yard shirtless. Often sit on my deck in the evening shirtless. It’s my property and I like to be comfortable.
Motel pools, beaches are also often places I’m shirtless. Sometimes hiking too.
At a pool, around the house, sleeping, sometimes when playing tennis or running outside.
Practically never.
But I suppose if I’m ever arrested, that seems to be the time men are most shirtless. That even happened in my neighborhood once when the police thought a shirtless guy may have gone through my yard. I even had a bunch of shirts hanging out on the line but I guess they were of no interest to him.
On the beach, in the ocean, in my house, and on my back porch. Even just walking to the beach I put on a T and take it off when I get there.
I thought the stained white “wife-beater” t-shirt was de rigeur for detention, but I suppose the fashions are always changing.