The benchmark we (and when I say we, I mean me and my boys) aim for is to always look like bnei torah. Sometimes, that means a hat and jacket (shul, walking in the street on shabbos / yomtov), sometimes it means wearing long pants when everyone else is wearing short (like bike riding, hiking).
Standing in line at Lowes or Home depot, would mean for the boys to dress like bnei torah, and for me (who wears colored shirts – GASP!)to act in a manner that is consistant with boys who are bnei torah.
Not a direct answer to the quiestion, pehaps, but those are my 2 cents