In a previous post Wayne Whitney wrote...
The 10 year-old roof on my house has no drip edge on the eaves, but
the bottom layer of architectural asphalt shingles hangs over the eave
by about 1". The bottom edge just dangles over the gutter. There's
no snow here, only rain (Berkeley, CA). Is this a reasonable/adequate
practice? Would adding a drip edge underneath the bottom row of the
shingles be feasible/beneficial?


Yes. If the bottom of the drip edge is below the top of the gutter, then
you won't get wind blown rain behind the fascia. My house does not have
drip edge flashing and on a 2:12 pitch the water runs back under the
roofing and down behind the fascia.

I didn't install the roof and curse the SOB who did every time it rains.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA