I have always worn yellow but I may go green for my next one. Green tends to signify first aider and I am a recently certified mental health first aider
Whatever one I happen to have in my car at the time.
Was a brief time I only wore orange due to management being bell ends by proclaiming only management can wear orange hi vis. Funny thing was it meant after a while the only high vis they had to give people were the orange ones as they were still ordering them in the same quantity.