Start looking now, so that when she has a buyer, the sooner she can move the better. The problem is, if she finds the home of her dreams, and then can't sell the home she is living in, it can be disappointing. On saying that, it is a good idea to sell your property first, get the money in the bank, rent a flat and you are in a much better position for buying - you are then a cash buyer and can negotiate a cheaper deal - everyone likes a cash buyer rather than someone with a place to sell. Buying/Selling usually takes around three months.