Is it worth making a separate DATE table or not? If I have a table like this:

my_table
=======================
id    date    some_data


Does it make any sense to pull the date out to it's own table? The date field would use the date data type. So it would now look like this:

my_table
==========================
id    date_id    some_data

dates
==========
id    date


According to MySQL, date data type = 3 bytes. The date_id would need to be a max of MEDIUMINT (3 bytes) in order to get the same result. A normal INT or BIGINT exceeds the storage requirements of a DATE type.

A downside to a separate table is that the queries would be more complicated because I am joining another table.

Are there any other ramifications that need to be taken into account as to whether or not to split the date field into it's own table? My gut reaction is that it's not worth doing unless you are dealing with a small set of dates (small enough to use TINYINT or SMALLINT).
Seems to me that is a classic example of over-thinking your design. 

Keep the dates in the same table so they can be easily indexed with other columns if necessary, and not take up 3 times as many bytes, and not make life a living hell for future developers.