I've gotten interested in knit, pique, short-sleeved polo shirts - in particular those of Lacoste. But regarding any knit polo shirts, what's the "rule" determining if it should be worn out or tucked in? a) Depends on if it has side vents (i.e. slits) or not? thus with vents it would be tucked in, with the idea a vent doesn't look good - particularly if the shirt is at all snug and the vents would flare; b) Depends on shirt size - if so long it would come down to the crotch area it should be tucked it in; another version: two-button - in; three-button - out; c) Depends on the formality of the occasion; I know, one doesn't wear a knit polo shirt to too dressy a setting but it surely is dressier and classier than ripped or distressed attire and the like; d) "My kind of thing": could it depend on the designer - i.e. if the designer shows in ads the shirt being worn out it means that designer thinks his or her shirt should be worn out and one should follow suit, or vice versa; e) No "rule" at all. If you are one who doesn't tend to believe rules exist in men's fashion at all you shouldn't be responding here - this is for those who believe rules do exist. And please don't respond something to the effect of "personal preference." I'm asking "rules" here. Or say "e." I suppose if one has a pot belly it could color one's decision, too. Or should.... Okay, I just noticed on Lacost's own website they show these shirts worn both ways (but mostly out, and the shirts don't look all that large on the models).