if i know I'm going to be riding all over town [ala saturday afternoon] then yes, I generally do wear a helmet.

if I'm riding to the store [7 blocks], my local bikeshop [4 blocks], coffee shop [5 blocks] or other super close destinations I rarely ever wear it.

however, if it's rush hour I try to wear it regardless of the length of the trip.

honestly though? it's been so warm that wearing it is a real drag and I've been leaving it home more than I should.

If I'm not wearing a helmet, then yes, I do wear a "beanie with a sideways cap". cycling caps are really well designed for their purpose.