Rule for accepting first date

[Jesper]

I propose the following rule to determine what we consider the date of issue:

The date of issue is the earliest date where the stamp(s) were available for use by the public.

There's a lot of confusion sometimes - GB #1 is known used from May 1, 5 days before "official" issue. Finland #1 is March 1, 1856 by "Imperial edict", but not delivered until March 3.
What do you think?

[BobSyl]

I agree with your rule.  Normally, I am only concerned with the first year of issue.  The actual date becomes important when you have a first issue on cover or on piece with a clear date stamp.  Who knows, you might have a first day of issue with great value!
Bob

[Jesper]

Another reason for the strict chronology would be if you try to order issues from different entities.
In some sense there are always more than one date that can be used as the first:
Ordering, printing, delivery to postal service, for sale and earliest known use date are some of them.
As usual we have to pick one  
I think we should work toward compiling as much info as possible. All the dates are interesting and useful in their own way.

[numones]

It is a difficult question.  As you say, the different dates all have their own interest, significance and importance.  Re: Panama for instance, citing Panamanian archives, Scott catalog says that #5-7 were printed before #1-4.  It does not say which ones got to the public first, just which were printed first.  

I think that even some of the accepted dates are only best estimates.  The same is true of quantities.