The general rule of thumb would be about three to five months before you want to move in. By allowing a few months you will properly be able to narrow down options based on your preferences, take advantage of any specials going on, and plan for the financials. It will also give you enough time to plan for the move, between renting storage, moving trucks, and packing. You definitely don’t want to make a hasty or impulsive decision on where you are going to be living and spending thousands of dollars.