PerfMad

As far as I know, the same model is recommended for some Toyota as well as Honda vehicles. So it could be that the factory gap of the spark plug matches the manufacturer's recommendation for one vehicle, but not for another vehicle? I'm no expert on the matter though. @Ruslan just for my info, is it not recommended to change the gap of iridium plugs at all? I mean can it damage the plugs - or any other reason?

@PerfMad @Izza this is mostly affected for Iridium plugs as the center electrode might become destroyed in the gapping process. although you can gap the Iridium plugs (If it's only necessary) by applying force only towards Ground electrode and not the tip (i find it merely impossible and costly affair if it's getting damaged in the process, so leave them alone). personally i wouldn't allow anyone to change the gap without knowing what they are doing, as usually for our cars gapping is usually comes as pre-gapped. has been replacing plugs on my previous cars with Iridiums and never had to gap them, ever!

https://ngksparkplugs.com/en/resources/set-gap-when-installing-new-plugs

https://www.densoautoparts.com/spark-plug-installation

The service manuals do not specify a change interval for spark plugs as the interval changes depending on the plug that is used. The 1K, 5K, 25K, 50K, etc...km preemptive service have an "inspect and change if needed step" and that is about it. 

Iridium plugs come pre-gapped. Do not try to gap them. Iridium and platinum plugs will typically last around 80,000-100,000km. A copper plug will usually last about half of that...but this is also dependant on the condition of your engine and its oil burning characterisics.