When working on your project file you are sometimes limited with number of history states. You can change it and add more but this have some side effects. First of all it will slow down your PS and some operations may take much longer to complete than before. This is because raising the number of history states will "eat" your RAM and this is cause for slowing down of your PS.
How can we bypass this? Answer is Layer comps.
Let's say that you have more than one Layer in your project and you want to make some changes to Blending modes, opacity, filters. But you want to be sure that you'll be able to return to this point if you are not satisfied with the results.
It is very simple. Just go to the Layer comps menu,
Select Create New Layer Comp,
Name it as you wish and click OK.
This will save all your Layers visibility, Position and appearance, and in any point of your work you would be able to return to this point and take other approach.
You can do this easy using these two arrows in bottom of Layer Comp menu.
See you!
