When should I start this process?

You can never start too early, but can most definitively start too late.  A general rule of thumb has always been to List your house with a real estate agent as many days before your move as the average home takes to sell (i.e. if comparable homes are averaging 89 days on market, you should list with an agent no later than 3 months before your projected move).  If you are going to try and sell the home yourself, we’d recommend starting a couple months before that.