If you search the forum, you'll find that this question has been asked many times.

Basically, there are no laws to say what tartans you can or cannot wear.

So, some folks will say wear whatever you like.

Some feel you ought to have the family name, or have been a member of the organization the tartan represents.

I think most of us are somewhere in between. We like to have some connection to the tartan, even if that means it's the tartan of your great great grandfather.

The main thing is that some do place great significance to tartan, so be prepared to talk about any tartan you wear. Know your tartan!