After the purchase of my first bespoke kilt about 18 months ago I received a gift from a family member which included.... matching tartan tie, sock flashes and pocket square!

I have worn the tie and pocket square with suits and blazers but never with kilt and even then the tartan tie and square at different times. (Matching tie with pocket square is a definite
NO!)
If wearing tartan then only one item but that's just my personal view.