Rapid plug failure in Chummy

[Charles P]

Haha, you are obviously more wealthy than us in NZ Charles, genuine plugs can be quite expensive here and we are tight!. I also always buy up stocks of new old plugs where I can find them, they seem more reliable added to which genuine old stock plugs generally look more authentic in our engines than modern alternatives

You don’t need much baking soda per plug.

Like you Ian, I buy NOS when I see them. 
I bought two boxes of NGK A6s from Florida for $15. Had them shipped to our New York office and the admin director looked after them until I was next passing through. 
Very cost effective, even if the admin director did pointedly refer to them as “dork plugs”.