Ok so imagine if you will that maybe, just maybe I have curated a Valentines themed design. Would you:
A) Like it to print on the 7th - so you can wear it on the day
or
B) Print it on the 14th to celebrate the day?
or
C) Don't give a sh*t either way?
U decide
wotto
A) Like it to print on the 7th - so you can wear it on the day
or
B) Print it on the 14th to celebrate the day?
or
C) Don't give a sh*t either way?
U decide
wotto

Even if I bought it on the 7th, there's no way to get it by Valentines Day.
(sorry to be such a downer). But the earlier the better. It's better to be able to wear it on the holiday, rather than buying it on the holiday.
if you want people to not stress, post the design in the next couple days.
oh and put me on the list for dont give a smurf lol.
Pick something that is more love oriented than valentines day oriented and you'll be able to sell it the 14th :).
I also think it's a question of how holiday the shirt is. I default to woot on this one... often they'll put a holiday specific shirt a week prior, and then a more year-long wearable one on the day itself. Being a shirt-a-day site, to me it seems to make the most sense to celebrate holidays on the holiday itself. It might make it harder to sell a very specific shirt (Santa on Christmas, Cupid on V-day, etc), but if you can get something more peripheral that can be worn for entire seasons if not entire years, they'd not only sell whatever day you put them up, but they'd probably sell better in general than a more holiday-specific piece.