I never touch my turrets in the field... ever. I sight in for a 6" POI (path of bullet is no higher than 3", and max range is where it finally crosses 3" low), figure out that max range and call it good. For rifle, I'm nearly always within that range with my 7STW (about the only centerfire rifle I use anymore)
I will use the subtend of the scope to bracket a critter to see if i'm inside or outside of that POI range. If a longer range is needed, I use the tip of the bottom post, which is usually a 400 yard point of reference on my Leupolds (for most calibers).
The longest shot I've ever made was about 5 years ago on an Antelope in WY. I shot and hit him at 225, he went on a death run out to 488 and stood there legs locked swaying. My dad always said "The fun is in the shooting, once its dead the work begins". So I reset the steady sticks, estimated range with the subtend, used the bottom post as reference, figured the extra holdover and let one fly... nailed it right in the head. My son got it all on video LOL.
@Critter: Elevation does affect bullet path, as does Temperature. More than you would think actually.
@Everyone: Ballistics software is fun, it gives you good indication of whats going to happen but I always suggest people shoot targets at various ranges to verify the behavior of their own rifle. Ballistics software without a cronograph is fairly useless however.
One more thing: I have a online calculator with less details for quick calculations if anyone wants to use on the fly, its useful:
I wrote the original software 20 years ago just to teach myself the math, and get a better understanding of the mechanics of bullet flight. The software has undergone many revisions and is now half ballistics software, and have reloading load management software for various caliber firearms.
Its software *I* use, so its all setup for convenience... which many people love and find as useful.