Least Used Metric Socket/Wrench Size?

[Tom]

I'm making trays for my wrenches and started wondering if it's even worth making some sizes. So it got me wondering, what sizes are the least used in general? I'm voting for 18mm as I can't think of a single time I've ever used that size, but curious about others' experiences...?

[Wespa]

18mm might be rare in classic Porsches, but common for example in 90s BMWs and Saabs. I voted for 14mm, 15mm is another good candidate.

[PSU_Crash]

18mm shows up here and there in the JDM world. Fairly certain I've used it on some domestics too.
My vote goes for the 15mm.

It's entertaining that you even put the 10mm on the voting roster

[gb951]

15 mm

Surprisingly, there is a need for a 15 mm wrench or socket on every 944... Anybody know???

[jeyjey]

Yeah, both 18mm and 15mm are used regularly on my E36 M3.

I can't remember the last time I used a 12mm, but that could just be because my memory is crap.

[Tom]

15 mm

Surprisingly, there is a need for a 15 mm wrench or socket on every 944... Anybody know???

Oil drain plug!

[Wespa]

I can't remember the last time I used a 12mm, but that could just be because my memory is crap.

There’s at least one 12mm on the 944 that’s used somewhat regularly, though not as often as the oil drain plug..

[Thom]

There’s at least one 12mm on the 944 that’s used somewhat regularly, though not as often as the oil drain plug..

Coolant bleeder plug.

[dr bob]

For me, this is a drag race between 16mm and 18mm. The 16mm gets used on one car here, non-Porsche, but I'll admit that it's been a decade or more since it was last out of the tray. The 18mm even less. It fits upper inner control arm shaft nuts, a very rare application on Porsche cars.

[Thom]

Not sure I have ever used 11 mm.