A lot can change in a year. Mortgage companies in California issue preapproval letters for buyers who qualify with their company but they have to be updated on a regular basis. You should go talk to a lender now, if you would like to buy a house in a year. If your credit is not the best, they will give you tips to get in better shape by the time you need the loan. Plus, they can tell you how much money you need to save each month for a future down payment. In today's market, the competition is fierce for homes, so the more cash you have available the stronger your purchase offer will be.