"He said it's the plugs plus 2 coils that need to be changed."
Experience with other guys on this webpage is that if one coil is going the others may not be far behind. IF You have the Money now, it will save you cost and trouble in the future to change all the coils at the same time, maybe have him keep the good used ones for the future.
I had coil issues back around 20K miles. I am starting to have some stumbles now at 120K miles, which make me think it is happening again. I am almost sure heat is a problem for our coils. The first time I had coil issues at 20K, it started right after I was stuck on the freeway, dead stop, on a 105+ degree day for 90 minutes with the AC on. The engine did not over heat, but right after traffic got moving again, I had a bad stumble.
The reason I say I am almost convinced is that this year I replaced all the plugs and saw no issues with oil contamination of the coils, a common problem. Now, at 120K miles I have had some slightly rough running and even a good stumble with a flashing check engine light(Means your coils or plugs are misfiring). It has been in the 105-110 range for the past 2 weeks and I had the stumble last week right at the peak of high temps. It is cooler now, low 90s, and I only have an occasional rough running. So I am guessing the heat pushed my "old" coils over to run rough and even stumble on the hottest day.
Anyway, babble babble, The COPs are worth changing all in one shot if you have the money. They are just going to fail one at a time in the reasonable future. The main cost is the coils, since you already had to remove them to change the plugs.
Ditto the shotgun approach when you start having leaking cooling system parts. When one part dies, usually the degas tank, the rest are waiting to follow.
Plugs and coils are something anyone can do, it is just a real time eater due to tight spaces. Brakes are easy IF YOU KNOW what to do. Oil change, a no brainer.
If you are inclined, you might look into one of you local high schools or community colleges for a basic auto mechanic class for women. Usually you will learn everything we have talked about here and you will understand how to talk mechanese(not get ripped off).
Good Luck,
Jim Henderson