I have noticed that our mailman/mailwoman doesn't leave the parcel notices the same day the item is delivered ... luckily, I keep track of my mails being sent through tracked services, and I get delivery alerts. I usually go to the postal outlet to pickup my mail without the notice card - using my address and get my parcel (sometimes it works and sometimes it doesn't as the postal outlet person sometimes can track the mail using the address, and sometimes insists on the notice card - even though my mail tracking on canadapost.ca shows that the mail is available for pickup at the postal outlet - but I don't get the notice card. I usually get the notice card delivered in my mailbox the next day (after I have already picked up my parcels/mails from the postal outlet).
I never noticed the regular mail (untracked mail) delivery patterns ... may be the mail delivery person does skip the days ... I don't know how would I ever know about it or can prove anything unless it is tracked mail ... may be try sending yourself tracked mails every day, so that you get the tracked mails delivered every day for rest of the week, and this way you can figure out the mail delivery pattern ... it will prove that the mail delivery person does really skip a day here and there to make it a long weekend or extra long weekend
