Notifying users of item expiration

1. A system for providing a reminder to a user relating to an item, comprising:

determining, over a period of time and based on position data received from a portable device associated with a user, an arrival frequency of the user indicating a frequency with which the user visits a materials handling facility;

determining, prior to an arrival of the user at the materials handling facility and based at least in part on the arrival frequency, a first date corresponding to a first anticipated arrival of the user at the materials handling facility;

determining, prior to the arrival of the user at a materials handling facility and based at least in part on the arrival frequency, a second date corresponding to a second anticipated arrival of the user at the materials handling facility;

computing a first difference between an item expiration date associated with an item previously picked by the user and the first date;

computing a second difference between the item expiration date and the second date;

determining, based at least in part on the first difference and the second difference, that the item will expire after the first date and before the second date; and

in response to determining that the item will expire after the first date and before the second date, transmitting a reminder to the user, the reminder recommending that the user pick a replacement item from the materials handling facility during a visit by the user that corresponds to the first anticipated arrival at the materials handling facility.

2. The system of claim 1 , wherein the reminder is transmitted to the user prior to the arrival of the user at the materials handling facility, and wherein the reminder is transmitted as at least one of an electronic message, a short message, a multimedia message, a physical message, or a voice message.

3. The system of claim 1 , wherein the reminder includes at least one of: automatically adding the item to a pick list associated with the user, or presenting item information associated with the item on a web page accessible to the user.

4. The system of claim 1 , further comprising:

receiving an indication of an amount of the item remaining at the item expiration date of the item.

5. The system of claim 4 , wherein the indication of the amount of the item remaining is based at least in part on: receiving from the user the amount of the item remaining, receiving an identification from the user of the amount of the item remaining, or receiving from the user an image of the amount of the item remaining.

6. The system of claim 4 , wherein the indication of the amount of the item remaining is used to update a consumption pattern for the user with respect to the item.

7. The system of claim 1 , wherein the arrival frequency is further determined based at least in part on a time between a plurality of arrivals by the user at the materials handling facility, or information provided by the user identifying an anticipated next arrival date.

8. A computing system, comprising:

one or more processors; and

a memory coupled to the one or more processors and storing program instructions that when executed cause the one or more processors to at least:

determine, over a period of time and based on position data received from a portable device associated with a user, an arrival frequency of the user indicating a frequency with which the user visits a materials handling facility;

determine, prior to an arrival of the user at the materials handling facility, an item expiration date for an item previously picked by a user during a prior visit to the materials handling facility and from an inventory location within the materials handling facility;

determine, prior to the arrival of the user and based at least in part on the arrival frequency, a date corresponding to an anticipated arrival of the user at the materials handling facility;

compute a difference between the item expiration date and the date to determine that the item will expire before the date; and

based at least in part on the difference, send for presentation to a user, a reminder that the user pick a replacement item from the materials handling facility during a visit by the user to the materials handling facility, wherein the visit is prior to the anticipated arrival.

9. The computing system of claim 8 , wherein the reminder is transmitted to the user prior to the visit by the user.

10. The computing system of claim 8 , wherein the program instructions further include program instructions that cause the one or more processors to at least:

receive an indication of an amount of the item remaining at the item expiration date of the item.

11. The computing system of claim 10 , wherein the indication of the amount of the item remaining is based at least in part on one or more of: receiving from the user the amount of the item remaining, receiving an identification from the user of the amount of the item remaining, or receiving from the user an image of the amount of the item remaining.

12. The computing system of claim 10 , wherein the indication of the amount of the item remaining is used to update a consumption pattern for the user with respect to the item.

13. The computing system of claim 10 , wherein the program instructions further cause the one or more processors to at least:

provide an incentive to the user to encourage the user to provide the indication of the amount of the item remaining at the item expiration date.