I dated a very devout Mormon for a while a few years ago who wore temple garments. He said he started wearing them after he got his Temple Card, which involved a lot of additional classes and study because Temple Cards are something you have to work for. Apparently they're something you can lose too because sometimes he would say things like "I could lose my Temple Card for that!" The way he described it, garments were part and parcel of having a Temple Card. He felt strongly about wearing garments.
I never saw them (felt them once but that's another story), but he said they were available in a couple of different fabrics and women could get sleeveless garments. He complained that the fabric didn't breathe. I had read that temple garments had embroidered symbols in various locations that stood for different tenets, but he wouldn't really confirm it. He just said "yeah, something like that." He was evasive, but that was because anything related to the Temple is sacred and to be kept secret from non-Mormons.
He did admit to knowing some people who were always physically covered by their garments. If they were changing garments they would carefully remove the old garments while putting on the new at the same time. Kept them on during intimate moments, showers etc. Not everyone goes to that extreme.
Deborah Laake wrote a book a few years ago called Secret Ceremonies that some people thought was very accurate and others thought was complete hogwash, but she had some vivid descriptions of garments and Temple. He didn't say what she wrote was untrue, but was distressed that she would violate the sacredness of the Temple rites by writing about them.