Generally, the halacha is that when a person makes a bracha on a food, the bracha is in effect so long as he does not change his location. If one changes locations (i.e. leaves his house), thebracha is no longer in effect. There are however various instances in which a bracha can remain in effect even upon a change of location.Rav Moshe Feinstein writes (Igros Moshe O”C 2 57) that if one continuously eats a food while changing locations, no new bracha is required on that food. For example, if one made a bracha on a sucking candy while in his home and then leaves his house while still sucking the candy, no new bracha is required to finish the candy.
Another exception to the general rule applies to travelers. One who travels while eating is not considered to have established himself in any location and therefore his bracha is effective even upon a change of location. If one makes a bracha on a food while in his home with the intention not to stay in his home for the duration of eating the food, he is considered to have not made a kevius for his bracha and no new bracha must be made when he leaves his home (Igros Moshe O”C 2 57).
This is a practical matter for erev Yom Kippur when many people have the minhag to suck candies all day. If one makes a bracha on a candy, with no intention to remain in the location in which he makes the bracha for the duration of eating the candy, he does not have to make a new bracha on the next candy when he is finished the first candy. For him, a change of location does not necessitate a new bracha.