I played in the 3 club comp just before christmas, and carried 5 iron, 8 iron and putter (putter was compulsory).
My reasoning behind my club choice (yes, I did put some thought into it!), was that I can hit all of the par 3s with a 5 or 8. As it happened, I hit all of the par 4s with the same clubs as well.
I'd been a bit ropey in the weeks beforehand, yet with such a paucity of clubs to choose from, I had more pars that day than I had had for weeks.
I can honestly say that if I could have carried a driver and SW, I wouldn't have wanted for any more clubs. Of course, that might only apply to my home course.
So, there are more than half of my clubs that don't get an outing on most of my games - at this time of year, notice the ones that haven't got a speck of dirt on them.