The psychological factor

I also think the concept of 'where the knob is pointing' influences my behavior too. One remedy is to just concentrate on DB. Most listening above 90 is loud! While pleasant, you probably hope for dynamic ranges within 50-90db. Depending on the music, one trick is to have a usable db that gives some excitement when it deserves it. 70 seems good, regardless of the knob, you can use an app or some other way to measure, but it will help you maintain your sanity. 

hilarious MillerCarbon.  You guy's are forgetting the cartridge output, phono stage gain setting, etc., plus if you have a remote control with the volume, of course the knob doesn't move when you raise the volume on the remote. Lastly, every record is recorded differently which sometimes changes the volume at a given setting.

Bottom line, turn it up to where you like and avoid getting hit with things by or screamed at by your wife. My wife is scared to go near the stereo, but she sure as hell knows where the volume knob is ......it's like an unwanted extra remote control.

How much current your preamp can deliver matters, as well as the sensitivity of your amp.  My Audire Diffet 3 will push three amps with not problem.  Of course,  it needs more volume to do this, but never needs anything past 12:00.  It might push 5 or six amps.  Audire's Julius Siksnius was always a huge power supply freak, as indicated by his two 500 watt trannys and 8 26,000 mf caps in his 125 wpc amp, compared to two 375 watt trannys and 4 4000 mf caps in a Bryston 200 wpc amp.  

I am with Kijanki, use the gain provided by the preamp. Likely will sound better when using  50-75% of it's gain. With digital there are many preamps that provide too much gain. Having an amp that allows a choice with it's gain is a plus.

Wouldn't it be better to have the preamp matched to the amp, so that at the amps max output the preamp volume control would be up above 12:00 taking the deficiencies of the volume control out of the equation.