The registered requests I have sent, I never experienced success with - so I stick to normal mail now and will continue to do so for as long as I collect.

Like others have said it is an inconvenience for the person on the other end, especially as there's an issue of who signs for it if the celebrity is not accepting the mail personally.

It will make things worse. If you send to say Johnny Depp and register it; he has to sign for it. Obviously he isn't at that address to get the letter so it will end up coming back to you as undeliverable or unaccepted.

TBH I seriously doubt certifying or registering a letter will increase your chances. If anything it will greatly decrease them, for the inconvenience you caused.

I've never used registered letters. It probably inconveniences people at the other end so I wouldn't bother with it myself.

Registration of the letter ensures it's delivery but as I heard it could slow down it's delivery time and costs additional fee. Do you use registered letters and do you have any experience with them?