How long does it take for them to check the link? I sent an email with a unique link in it to my @Outlook.com account 6hrs ago, and there have been no visits t

How long does it take for them to check the link? I sent an email with a unique link in it to my @Outlook.com account 6hrs ago, and there have been no visits to the link. The email is in my inbox (though I have not opened it). Does this only happen on opening the email (in the Outlook web ui)?