Save a search once and let it watch the market for you, in the mail and in the site.
Any search can be saved, filters and all: the words, the category, the district and the price bracket travel with it. Saved searches live in your account and can be renamed or switched off one at a time.
Once a day Chux collects what is new against every saved search you left switched on and mails one message, not one per listing. A quiet day sends nothing at all.
Each kind can be turned off on its own under notification preferences, and every one of them appears in the site's own notification list whether or not the mail is on.