Some people think that waxing skis and boards just makes them go faster.  It also makes them turn easier, perform better, and helps preserve the life of the base material.  How often you wax depends on how serious you are.  While most dedicated skiers probably average about every four days, you should wax no less than every 10 ski days at the very max.  A typical hot wax runs about $15 and you can have it done at your local shop before you leave on a trip, or drop them off at a resort shop after skiing and pick them up in the morning.