Depends on the smoker type, proximity to heat source, heat output, amount of air getting to smoke wood and mods, regarding time the chips/chunks will smoke. You can get long smoke time from chips if you dial-in the heat and air, but chunks are easier if higher heat and smoke output is desired for a particular meat, or when smoking in inclimate weather. For chips to produce a long smoke, a fairly snug package with some form of air control on the box is a good start.
Eric