I have had many people ask me about intonating their acoustic guitars, and not one of them actually needed any attention, accept for this one.
In this case the guitar was actually OUT of tune, possibly from shifting around over a couple three decades or so. A early Larrivee built in Victoria, BC - beautiful sounding guitar, one of the nicest sounding guitars I've played in fact, but poorly out of tune. We chose to move the saddle location, as it needed to be bumped just a couple millimeters. In many cases the entire bridge would need to be removed and reseated , along with new string slot holes, bridge plate, refinish, etc. That's a HUGE job, and one I will steer clear of other than a last resort with an old guitar like this. The chances of changing it's big airy tone is just too great to gamble on, beside the cost would be quite high for the customer (who just purchased it and was eager to begin recording with it). The gamble with this job was being very little room to work with in re-placing the saddle, as the width of the bridge was quite narrow. Choosing an extra wide bone saddle allowed me to compensate it correctly in the position I chose, and ultimately preserved if not improved the guitars' sustain and tonal spectrum.
I began by first filling the old saddle slot with a strip of wood with similar color and grain to match the bridge. It's set in with some Titebond wood glue and left for a couple days. When I come back to it I set up my router and shave down the protruding fill until it's flush and map out my new placement with a pencil. I use a combination of a ruler and the location of the old saddle to fine tune it's new location. When I'm satisfied with it's new location, I drill off each end of where the new slot will be cut to allow the entry of the Dremel blade. I then bring out my acoustic saddle cutting jig (you can pick those up at www.stewmac.com, my favorite toy shop) and set it up. These work great in most cases, they help keep the Dremel blade cutting straight while you glide it across the bridge. After that is done, I cut a new bone saddle out of a raw blank and intonate it accordingly.
All in all it turned out great to both our satisfaction and the cost was minimal to fix what was previously an unusable instrument.