Batch numbering convention...?

[TekelBira]

Here comes another "silly" question: What are the four digit numbers for brews you have in the primary, secondary, in bottle, etc.? Dates?

 

[homebrewer_99]

My numbering system identifies the year (2006) and the batch number (12) as in 6012.

I use the 4 digit Julian calendar system at work so I just do the same for my batches.

I cold use just 3, as in 612, but after 34 years of using 4 numbers my brain is more geared that way.