You would use the process of step and repeat in photoshop to duplicate items and evenly space them. Designers may be familiar with the process as it is included as a method to space items in other Adobe applications such as Illustrator and Indesign.
For this example I am going to step and repeat a swirl motif that could later be used as a border for example.
To start off with, open a new document and have the item you wish to step and repeat on a seperate layer from the background. It this case a swirl. I am using a vector shape, but you can also follow this process with a raster image or even type if you wish.
First you need to duplicate the image. Make sure the layer with the object is selected and hold down the alt or option key as you press the Ctrl & T keys or Option Apple T on a mac. By including the Alt/Option in the transform it means that the next step will make the changes to a copy of your initial object not the original.
You should still have only the background and the object layer in the layers palette, but with the transform controls surrounding the object.Click on the object inside the transform controls and drag to where you would like the first duplicate to be positioned. (To keep it perfectly inline either horizontally or vertically hold the Shift key as you are moving the duplicate). Press return key when your happy with the posistion of the duplicate.
To repeat this process of both duplicating and moving the image all you have to do is press Shift Alt Ctrl T / Shift Option Apple T. Continue to press this combination of keys to continue to step and repeat the object.
The same process can also be used to make complex patterns. Upon making the first duplicate and moving the duplicate to a new position try scaling down the image and rotating it before you then duplicate the layer and repeat. All of the examples below have all been made with the original shape used above.