I cannot fathom what is so hard about remembering to make an Eiruv Tavshilin?
Just as I remember to eat my breakfast, or turn on the air conditioning, or to go to Shul or to lite my Chanukiyoh or to count the Omer or go to work, so likewise I take an Eiruv Tavshilin into stride and remember to make Eiruv Tavshilin.