I used to work in an office where a colleague would decree when this was, but now I am never sure when to do it. Easter is usually a benchmark tho.
I shaved my legs earlier this week and wore a skirt with bare legs on Wednesday and Thursday but that was for lolling about the house and doing Easter holiday stuff; now it's back to work (I work in a school) so I am not sure if that counts. Once it's done, you cannot go back - so have you gone for bare legs yet?