NGK Iridium plugs (Honda OEM) are rated for 100k miles, and they're reasonably inexpensive. Watch a few youtube videos and learn to change them yourself. I change mine every 50k miles. That's just my preference.
Back story: . I've had numerous Hondas for close to 20 years, all purchased and serviced at my local dealer. I'm happy with the service I receive there, and with coupons and discounts I think I get reasonable value for my money. Of course they always offer their recommended services at their service intervals. I'm pretty adept at declining superfluous services like "ethanol service," "fuel intake service," etc. Achieved over 125K on all my cars with only official prescribed services at reasonable intervals, plus BG MOA and BG 44K.
I currently drive a 2016 LX w 21,000 miles. I got it last year at 7,100 miles. It was a smokin' deal on a certified pre-owned, plus free oil changes for 3 years. Anyway, I've never had my plugs changed in my Accords and Odysseys over the years. Other than the Maintenance minder codes I can't seem to find any reliable official information online regarding the spark plug change interval for the 2016 CRV. A google search turns up mostly dealers' websites that all say changing plugs is 30K mile service.
I'm inclined to to call BS to 30K miles after reading through numerous forum posts (and answers, thanks!), knowledge of the longevity of iridium/platinum plugs, and personal prior experience. My gut tells me 100K miles but I'm just looking for official so I can decline this service at 30K with confidence.
BTW, the dealers also recommend valve clearance check at 30K miles. Is this necessary? Wouldn't they have to pull the plugs to do this? Is this just coincidence?
No, you don't need to pull the plugs to check valve clearance. It only requires removing the valve cover. I've always read that valves should be adjusted at 100k miles. 30k seems a bit early to me.
In my experience, the dealer will always try to get money out of you while they have your car. It's much easier to slip in an "extra" service rather than have you come back another time. Also, considering how overpriced the dealer service is, I'd rather wait or do the service myself and save the money.