Make a list of the companies/organisations etc that you expect to receive mail from and the dates that you expect to receive mail from them. You can then check them off as their mail arrives and spot the missing ones.

It is surprising how many will say they have updated your contact details, but still send mail to your old address. I am sure that some places have more than one address book for different departments or offices.

Don't forget the annual subscription notices from AA, St John, etc.

I also suggest getting as much of your mail as possible changed to email.

Good luck with the shift and your new home.

Behodar: My understanding (which may be wrong!) of the mail redirection is that any mail addressed to your name at your old address will be redirected by the post office (scanning/OCRing the address), before it actually makes it to the old house.

Only for a few months, you can then pay to have it extended to six months or something, and after that you're relying on the good graces of the new owners.

Which negates my other suggestion of setting up the home automation to fire up the A/C at 3am and open the garage door at random intervals, then plastering and painting over it so it can't be found: Haunted house.