@every(minutes=0, seconds=0)

method will been called every minutes or seconds

@every(minutes=24 * 60)
def on_start(self):
    for url in urllist:
        self.crawl(url, callback=self.index_page)

The urls would be restarted every 24 hours. Note that, if age is also used and the period is longer then @every, the crawl request would be discarded as it's regarded as not changed:

@every(minutes=24 * 60)
def on_start(self):
    self.crawl('http://www.example.org/', callback=self.index_page)

@config(age=10 * 24 * 60 * 60)
def index_page(self):

Even though the crawl request triggered every day, but it's discard and only restarted every 10 days.