What about kernel "optimize for size"?

[Steve Snyder]

I'm having a hard time understanding the thinking of the FC developers 
regarding the kernel "Optimize for size" option.

Earlier 2.6.x kernels had this disabled, then they enabled it for a while, now 
it's disabled in current FC4 kernels.  Meanwhile, the current RHEL4 kernel 
does enable the  "Optimize for size" option, albeit with earlier compiler 
(GCC v3.4.4) and kernel (2.6.9. + patches) version.

What's going on here?  Does the value of this option change with differing 
kernel versions?  How does one determine empirically whether this option 
should be enabled or not?