InDesign's Transform Again commands are very powerful. When you choose Object > Transform Again you'll see four options: Transform Again, Transform Again Individually, Transform Sequence Again, and Transform Sequence Again Individually. How these commands work is far from obvious, so I'll explain them here:
First, you need to understand what, exactly, a transformation is. In the world of InDesign, a transformation is a move, rotate, scale, flip, shear or fitting command. These transformations can be applied to a selected object through the Control panel, the Transform panel, interactively with the Selection, Direct Selection, Free Transform, Scale, Rotate and Shear tools, or via the commands in Object > Transform.
This one's simple. It just repeats the last single transformation you applied to an object. In the example below, I've option/alt-dragged the left-hand photo straight up to create a duplicate.
Now, leaving the duplicated photo selected, I choose Object > Transform Again > Transform Again and the object is duplicated and moved the same amount as the first copy.
You can also use the Transform Again command to apply a transformation to a different object other than the one that was originally transformed. In the example below, I selected the third, fourth and fifth photos, and then chose Object > Transform Again > Transform Again twice.
Transform Sequence Again
This command behaves exactly like Transform Again, except that it can apply a "sequence" of transformations. In the example below, I've rotated, scaled and moved the left-hand photo.
Next, I select the second photo, and choose Object > Transform Again > Transform Sequence Again, and the same sequence of transformations (rotation, scaling and moving) is applied to the second photo.
Transform Again Individually
This will allow you to apply a single transformation to multiple objects, but with the transformations applied individually to each object. In the example below, I've rotated the left-hand photo.
If I select the other five photos and choose Object > Transform > Transform Again, the five photos are rotated as a group, as if they were one object.
If I undo this, and then select the other five photos and choose Object > Transform > Transform Again Individually, each rectangle is rotated separately.
Transform Sequence Again Individually
This command is just like Transform Again Individually, except that you can apply a Sequence of transformations individually to each object. In the example below, I've rotated, scaled and moved the left-hand photo.
Next, I select the other five photos, and choose Object > Transform > Transform Sequence Again Individually, and each object is rotated, scaled and moved individually.
These commands, particularly Transform Sequence Again Individually, have saved me lots of time and grief on various production projects over the years. Store this information in a corner of your brain somewhere, ready to use when you encounter the need to transform multiple objects.