Special Effects has no expiration date.

Their sort of right as I think Special Effects proabbly said the three month thing to include BAF Yellow which is different from the other dyes and lasts less time (probably only around 3 months or so before going a mustardy colour).

To comply with EU regulations on these type of products being sold in the UK & EU, dyes have to last a minimum amount of time before opening (shelf life) and after opening.  When we started selling these dyes we contacted Special Effects for clarification that their dyes complied (otherwise we could not import them into the UK for sale).  Thankfully they confirmed that their dyes last at least 30 months from manufacture and at least 12 months after opening without any adverse effects, although the colour can change the longer it has been since it was opened.  The exception is BAF Yellow which discolours very quickly and normally only stays a true yellow for a few months and therefore we cannot import this in the UK for sale as it does not comply with the EU regulations on hair dyes and cosmetics.

That aside many many people have said to us they have used dyes that are years old or that have been opened more than 12 months previously all with no problems so the above dates are the minimum they should last but I would not throw out a dye older than this but instead mix it well to ensure good mix of all colour pigments and then try a strand test.