After you submit a request, we check that the request is a suitable request for our suppliers to quote upon. The vast majority of requests (>96%) are approved. The ones which are not approved are flagged as "denied" within your account. You can learn more about denied requests here:

Why has my request been denied?

Most requests are approved within a few minutes. But a certain number are flagged for extra manual checks. These manually checked requests are normally approved within a matter of minutes during office hours, but this can take longer at night and over the weekend.