My 3-coat unpainted fairly rough texture stucco is 15 years old and has
a lot of hairline cracks (less than 1/16") which isn't surprising since
I live in earthquake country (Northern California). In one place next
to a window, enough color coat has chipped off so that I can see the
crack goes into the brown coat.
Since I'm worried about water penetration (a neighbor has measured
gusts of 87mph and rain sometimes seems to be horizontal), I'd like to
repair the cracks. After talking with a number of people and doing web
research, I ended up with lots of information but no consensus on how
to do the repair.
I've summarized my findings below and would appreciate comments
regarding pros and cons that are based on actual experience. Thanks in
There seems to be two general categories of repair, cement/stucco based
and paint based, each with several variations. References are marked
with a number in brackets, e.g.  and are given at the bottom.
Remember the below is only for hairline cracks.
1. Cement/stucco based repair
Advantage: Still have low maintenance stucco finish
Disadvantage: Repaired cracks will almost certainly be visible
Options 1.1 and 1.2 are similar but slightly different.
1.1 Mix portland cement or stucco with half-and-half acrylic modifier
and water. Apply with putty knife. Work to match texture. Apply fog
(color/finish) coat afterwards. No need to widen cracks. 
1.2 Apply a acrylic multi-bond (green from one vendor), let set 34 to
45 minutes, apply a one-coat stucco matching texture, apply fog coat
after a couple of days. 
1.3 A variation of 1.1 and 1.2 is to apply a new fog coat to all the
stucco, not just around the cracks. This "should" make the cracks more
invisible than any other method. I'm not sure how well this will work
over my rough texture. Seems like this might also be a relatively high
cost option. (Can't recall where I heard of this alternative.)
1.4 One stucco person who covered a small addition for me a few years
ago, upon seeing I had some old color coat mix (left over in a bag) and
a stained area of stucco, suggested I could take the stucco mix, add
water, strain, and spray the "colored water" onto the stucco. I wonder
if this would work to make the color uniform after 1.1 or 1.2? Also
this sounds expensive (and a waste) to buy new stucco mix to do this to
the whole house.
2. Paint based repair
Advantage: Finished job will be uniform color, possibly hiding
Disadvantage: Now have a painted surface to maintain/repaint.
Common: Fill cracks with Elastomeric Sealant (brush grade) or perhaps
Still need to match texture, given recommended 2" width for
so patched cracks might still show through new paint coat.
2.1 Paint with Elastomeric Paint 
Advantage: Some stretch to keep very small new cracks from
Disadvantages: Costs more than regular paint per gallon and much
Reports it is harder to apply than acrylic latex
Reports that it creates a vapor barrier which can
if moisture gets trapped behind.
Notes: Manufacturers have different recommendations for number of
Need to monitor application thickness.
2.2 Paint with Acrylic Latex 
Advantage: Less expensive, easier to apply. Does not create vapor
Disadvantages: May not have stretch to cover new cracks.
 John J. Bucholtz, "The Consumer's Stucco Handbook" (30 page
 advice from Stucco Supply store
 "Kel-Seal Elastomeric System, a Technical Guide to Elastomeric
(9 page pamphlet picked up at paint store)
 Suggestion from paint store and several news group web postings