I use my inner self. Seriously - if it feels right it is right. That is what works for me.

I have sat with TV directors in a control room as they sit there and simply count 1-2-3-4: Take Camera 2; 1- 2- 3- 4: Take Camera 1; 1 - 2- 3 - 4: take camera 4 - and so on. One of the most asinine things I have ever witnessed IMO. But also have been told by many, many TV people that is for sure how it is done in TV...and one view of most music shows tells me this is sadly true. I have talked to film editors who follow the same "rules" - don't hold on a long shot longer than x amount of seconds is a common one. To me any set of editing "rules" is rubbish.

I worked as an editor on one film a long time ago - in it was this looooooong church scene. The director clearly was trying to tell a story with this scene, as well as the film. The producers kept complaining that the director had no idea how to make a film, the shots were too long - the scene was too long - the "spiritual" overtones in thefilm were just boring, blah,blah. They kept telling me to cut this 15 minute church scene down further and further until it was about a 30 second shot of the preacher saying something like "God watches over us...Amen" I would argue about how they could say it was shot wrong, or that the story was important, and they would come back with how such and such a book explained the correct way to shot, and edit, scenes. Another 'classic' comment from these same producers was on another film where an actress was, *gasp*, actually acting - her recation was awesome. You could see her face just emote. I left her CU a bit longer because the acting was so good - it went from the dialog to her registering what had been said and than slowy her face went into a sad, hurtful mode and than into crying. I was asked to cut the bulk of the shot because "no one wants to see her acting". The shot became a "standard" cut to CU/reaction shot of her crying, sans any real reaction (acting) to the dialog that caused her to cry.

Before people start up on me for saying this - keep in mind there is "atuomated" software out now that uses these types of settings. Clever and maybe useful but part of what an editor is supposed to do is - well, edit! The classic film editing example that has been around since it came out has been the shower scene in Psycho. Recut many many times - a frame here and a frame there - until it 'felt right'. Also another story was about John Ford who wanted to convey a feeling of being alone, an uncertian future. The last shot he wanted was of John Wayne on a horse - sort of riding off into the sunset. But he wanted it shot from a few miles away so that all you saw was a vast desolite landscape with a lone rider in the frame. Editoral, and studio, tells people the formula is Master/Wide/Establishing, Medium/MCU, CU. And Ford new this but did not want to end on a CU of Wayne. So he made a directorial choice for the editor and the studio. He shot the other shots but made sure they were unsuable - bad framing, out of focus - whatever. The only usable shot was the mile long master. Broke the "rules" but certianly it "felt right".

I go by the tempo of the scene. Action or high energy I tend to cut very quick 1.5-2 seconds at points.

If there is camera movement I feel you can hold a shot much longer than on a locked down shot.

Tend to cut alot to follow dialog. I hate when people cut too soon, but that is more something you just feel. I also will go back to something several times after working on other things. A clear head and a good nights sleep will let you see things different.

And obviously if you are cutting to a musical score, it will give you some direction on timing too.

I still feel 10 seconds is a real long shot - there better be something really special to see, but there are plenty of exceptions.

As a general "rule" I hover between 4.5-7 seconds, but it really just takes time to find the right fit.

If there is a magic formula - that would be great, but then again - we could all be replaced by machines if it was that easy LOL.

There is no magic pill. Its a "feel" that varies from shot to shot, and depends greatly on what you're looking at.

Two of my favorite examples of really good editing happen in two popular movies. The first, Terminator 2 where the first chase scene and what goes down right before is about as good as it gets. The second is the opening thirty minutes or so of Full Metal Jacket, during the boot camp scenes. Rarely are movies that compelling that you almost feel part of what you're seeing. Cameron did a great job in T2 and Stanley Kubrick did a great job in FMJ.