So I just needed to get TWO ignition coils replaced. I'm surprised that two coils would bite the dust at the same time. Is it understood why this might happen? Or is is just a crazy coincidence?

 

If they are rears they get hotter , prob just a coincidence .

 

Common sense would be to replace all coils at once to avoid future failures.

 

Age is generally why coils of this type go bad in pairs or sets at a time. The components making up each coil or coil pack begin to get high resistance due to material break down.
As suggested as a DIY it is better to replace them all. A service shop however generally , at least here in the USA can recomend or suggest the replacing of all but need to be careful and document exactly why such recommendation for replacing parts that have not yet failed. Damn insurance and state laws....

 

To Me Common Sense ain't that common at all , imo not just on the interweb , seems to be everywhere .

So a good suggestion replacing all , as atm they be cheep as chips with those all in one packs (cops/plugs/filters and gaskets) available .

 

Thank you, everyone. They were two "rear" coils, which required a lot of work to get access. As a result, they replaced all three rear ones. If the front ones go out, it won't be as big a deal to replace, they say.