If you've ever wanted to suppress a feature if a parameter reached a specific value, there is a great way to do this at the feature level. To see how this is done, I will create a rectangular extrusion with a shell on it that has a condition to suppress the shell if the size of the rectangle gets below a certain value. To do this I will just create a rectangle with two dimensions for width and height and specify a name for at least one of the dimensions.
Extrude the rectangle to create a 3D model and add a shell with something like 0.5 in.
Here is where we will add the conditional suppression. Before we add the conditional suppression you will want to make sure you have renamed one of the parameters on the rectangle sketch. If you don't rename one of them, you wont see the dimension for the conditional suppression. Right click on the shell feature in the browser and select properties. Select If and choose the parameter that drives the width of the rectangle and specify Less than 2 and choose OK.
Now if we return to the 3D model ,we can edit the parameter that we renamed from 4 in to less than 2 in and notice that is suppressed the shell feature. Change the parameter back to 4 in and notice the shell shows back up.
I have seen some very creative ways people use this. If you want to take it past this you might want to take a look at iLogic which will let you do much much more.