Hello G-belle,

IMO...this painter is correct. BECAUSE- many technical manuals from paint mfs. usually state that after a month, most factory primers become "too brittle" or hardened-off to properly accept a new paintcoat.

* Are BOTH sides of the shake primed?? Hopefully they are!
* "Backpriming" helps reduce moisture penetration from the home outward thru the siding. This in turn helps the durability of the "weather" side, which is taking the beating!
* If it's natural cedar, I'd give a slight nod to Oil primer, with TWO topcoats of Latex paint. You should only need to reprime the "weather" side. That said, you wouldn't be "wrong" to reprime both sides though!
* Since I don't have your checkbook, this is your call...but definately reprime the outside surface. Check with painter about $$ for doing both sides.

Regards,
Faron