In use, I begin shooting on the warm up target...while conditions are typically best of the day, at the same setting I used last. This is usually close but may or may not need a small adjustment in either direction. If forced to "guess" before firing a couple of sighters, I can do so with pretty good results by moving or leaving it alone, based on temps. For example...say I last shot late in the day at 85 degrees and today it 45...I may very well start by moving the tuner OUT by one hash mark. I do this only because of the wide temp swing and EXPECTED change in tune as a result. All this gains me is a two or three less sighters shots, while tuning on the warm up target. One can very easily just start where it was last set and come to the same place. Either way, I may or may not be dialed in precisely yet and will base any further movement of the tuner on size and shape of groups on the sighters target. If I'm close, my next move will likely be something less than a full mark on either or both sides of this setting. Gene Beggs said it very well when he describes it as being as simple as adjusting the focus ring on a scope. Many times with my tuner, the last setting used when last shot will still be in tune the next day...or week, and I don't need to move it. Same goes for shooting throughout a day or match...Many times I can shoot the match without moving it at all...but when I do, this is very important to remember. ...I'll always be very close. The biggest adjustment I've ever needed to make during a match and from a good tune, was two marks throughout the day. That was a day where the Temps went from around the upper 30's and ending in the 80's. The key is knowing what to do and when. This comes with time but it's not difficult at all. Some shooters bring 2-3 loads to the bench....I bring a tuner. Same deal.----Mike Ezell