To IS or not to IS

Hey everyone. I'm a new Canon convert, coming over from Sony. Sony has their IS built into the body, and Canon has them built into the lenses. Since there is an on/off switch, is there any reason to ever turn the IS off?

If your camera is on a tripod, IS will not do much good. Turning it off saves power.
On some older IS lenses, IS may even get confused by the lack of vibrations, and create some by itself instead.

When shooting action, where you are moving your lens/camera back and forth all the time to track irregular movement, the IS may lag behind, and create a "swimming" feeling in the viewfinder. Turning IS off gets rid of that.

IS? … oh, yes, I have it at one lens only which I use less and less. I mean lens with IS

I have it on most of the lenses I use regularly.

Other than using the tripod there is no reason to turn it off. Some lenses have 2 modes so you can use the IS while panning, but otherwise leave it on.

In my first post in this thread, I just gave you another reason to turn it off.