Ring Around the Collar: How dirty is my shirt I only wore for a few hours?

Factual Questions
1

How dirty does a shirt get if you only wear it for a few hours and don’t sweat or eat in it? How often would you wash such a garment? Especially considering it might need to be dry-cleaned or pressed…?

I have a habit where I only wear my “nice” clothes for a special events, and then I only wear them for a few hours (as in less than 5). I have this thing where I kind of gauge how dirty a shirt is, and how many times I’ve worn it and for how long of intervals before I decide “ok this needs to be washed.” This is especially true with my collared shirts, which I VERY rarely wear. In my head, I think “this shirt is not at all dirty” and just hang them back in my closet.

HOWEVER!

Recently I had to go to a wedding and broke out my nice dress shirts that I haven’t worn in years. Some of the whiter or lighter colored shirts had a gross yellow stain around the inside of the collar. This was not there when I hung it up.

I deduced that I probably should have washed that shirt before I put it away, but I probably only wore it for a few hours. I am guessing the oils and gunk that is always on our skin–no matter how recently we bathed–was funky enough that, given the years it sat on the collar, turned all gross colored.

Do I have to wash every shirt I allow touch my skin, no matter how briefly? Does our human funk permeate clothing every time we come in contact, and everything needs to be washed?

I wear an undershirt (black t-shirt) under everything. If I am wearing a graphic T, black undershirt. Flannel? Black undershirt. So my collared shirts only touch me on my lower arms and neck.

I assume my darker colored clothes don’t turn yellow because of the pigments, but I would assume they are just as “gross” as the yellow collared whites?

2

I’ll wear something a couple of times in a row if it’s a short time frame.

But anything that sits in my closet for more than a couple of months is going to get washed. As it will be covered in dust, pet dander, and other unsavory smells.

3

I happen to know something about this. (I’ll spare you the long, dull backstory.) The yellow stains are caused by the interaction of sweat, dead skin cells, and soap/shampoo/hair or skin product. The stains show up after the fabric has been exposed to heat, such as body heat from a second wearing (even if it’s brief) or a hot closet.

For this reason, dress shirts should always be laundered after one wearing. I know it seems like a waste. And yes, these stains can happen on darker shirts, too, but the ring may not be visible. They’re not easy to get out, BTW, at least in my experience. Maybe someone else has a nifty hint.

4

Back in the day, I sometimes wore a high neck skivvy instead of an undershirt. It doesn’t show much, and it made a big difference to how dirty the collar got.