I generally hang on to my museum tag for as long as I can. Members get a different-colored tag from those who are just visiting. (Is that to make us feel special, or is it more to single out the other visitors - those who might be recruited for membership?) I've often wondered if the institutions change the tag color at some regular interval, or just when they run out of one batch and order another. Now that I'll be visiting every day for nine months, I guess I will figure that out. So far, I've been able to use the same tag each day. I'll see if it works again on Tuesday.