Rebuilding or modifying

I've noticed that the concept of rebuilding things seems to be fairly important in games. For example when you set an effect on a unit or remove it a reset attributes function is useful because knowing the previous state is hard.

To give an example in everquest you could cast a spell on yourself that made you stuck and then cast a shorter spell that made you stuck and then you could move around after the second one was done.

so you want to apply the effect then reset all attributes (or just some) based on the effect and your base stats.