I got sick of giving myself a headache every time so I follow batsbrew's advice and simply track conservatively. 

dubdisciple
I got sick of giving myself a headache every time so I follow batsbrew's advice and simply track conservatively. 

heheheh
 
it's just so much easier.
 
and cleaner.
with 24 bit recording, 
you are not losing anything by having plenty of headroom.

Personally, I usually end up mixing 'liberally' (not conservatively) (to almost 0 dBs (no headroom), THEN, forcefully reduce to a stingy -3dBs of headroom (input gain) on the master buss ... allowing for a 'few' stray percussive spikes ('red flags') on the pre-master buss.
 
Oft, my ears cannot tell and it seems a bit easier for me to mix by ear that way ... (in Sonar).  If the pre-master buss shows a lot of 'red flags' (clipping), I can more easily reduce the offensive track volume(s) that way.  But that is just my madness.

I had an epiphany about this a while back: http://forum.cakewalk.com/Hitting-the-red-I-was-wrong-about-this-m3065697.aspx
 

i just finished a mix that is -26db RMS,
and peaks at -10.
 
none of my plugs are any closer to 0 than -8db.
 
everything sounds pristine.
 
when i master it, i can easily get to -9rms with peaks at -0.3db, 
dynamic range of 8-9,
and it still sounds good.
 
why push the issue with guessing about metering?