1. Before you store the column be sure you have eliminated all traces of pH buffers (like phosphate buffer or formic acid) by pumping mobile phase without buffers through the column for 10 column volumes. Then pump the storage solvent!
2. Never use 100% water on a C18 column since it will cause column collapse. The exception is a HILIC column.
3. Never drop a column on the floor. Remember, it is a 'High Technology' item. Our modern civilization 'relies' on it fucntioning properly!