It really depends on the client.  Furnishing a new build property is a very exciting moment, especially when clients are purchasing an off-plan property.   Some clients prefer to do as soon as they reserve the property; others prefer to do it at later stages, a few months before completion.  In Spain there are two special sale periods, one that begins at just after the Three Kings holiday season and the other at the end of June, both periods last around two months.  Many clients like to shop during these periods as there are different discounts and offers; others prefer to purchase the furniture package that is offered by the developer.  Most buyers prefer to appoint an interior designer with a budget in mind, let them work on the design taking into account floor plan a few months in advance, receive different options, decide which option suits them best and plan the delivery on the date on completion.