When an alert is sent

A shopper asks to be told about a product on their own wishlist, one subject at a time. Nothing is ever sent about a product nobody asked about.

What an alert can be about

Subject	What it means
price	A product a shopper saved is now offered more cheaply than it was when they last heard about it. The comparison is against what was last mailed rather than against the price on the day they saved it, so a product that drifts down over a month is one email rather than thirty.
stock	A product a shopper saved while it was out of stock is back. It fires on the crossing rather than on the level — a product that has been in stock the whole time never fires — which is what stops the first sweep after an install emailing every customer you have.

One email carries every subject that moved for that shopper in one sweep, so a customer watching six products hears once rather than six times.

How often the sweep runs

Your store's own cron wakes Wishlist hourly, which is the finest cycle OpenCart's scheduler offers. What the sweep does when it wakes is yours to set under Sweep Runs, and it is one answer for the whole installation.

Sweep Runs	What it means
Every time the cron runs	Every time the cron runs, which is hourly
hour	Hourly
day	Daily
week	Weekly
month	Monthly

A store that has never swept sweeps at the next wake-up whatever the cycle says, so you find out this hour whether your choice works rather than next month. How much one sweep may do, and how long one product waits before it is mentioned again, are on the settings page.