I have had two fuel cells with foam in them. One is still going strong after many many years. The other broke down in about 3-4 years and clogged filters etc. If I were going to put in a new cell, I would not worry about it. If the cell is old, I would watch it closely. To be safe I always put my filter on the output of the cell and before the fuel pump to keep it out of my carbs should the foam break down.