Laws 14-93, 146-00 and 168 do not establish a term. The statutes just state that foreigners who come to reside permanently in the DR have an exemption to bring in their personal and household goods ("Las importaciones de efectos personales y del hogar, pertenecientes a extranjeros que vengan a residir definitivamente en el pa?s, y de los dominicanos que hayan residido en el exterior por un per?odo de dos (2) a?os consecutivos y regresen a establecer su residencia definitiva en el pa?s, siempre que no se les haya concedido anteriormente este privilegio. Asimismo, las importaciones de libros para uso personal de dominicanos que regresen definitivamente tras realizar estudios en otros pa?ses.")
An old regulation from the Customs Dept. established that the time period was 6 months from the time residency was obtained. This term may have changed since then. I'll find out and post the answer later.