I do take class because I still dance, and yes, I do slip into class with the Royal Ballet from time to time.
People often argue about this. Obviously one of the skills in performance is acting, and you can't expect every Romeo to really be in love with their Juliet!
I get to the theatre in plenty of time; I prepare my shoes in advance; I eat and drink the right things at the right time. The rest you have to leave to luck!
I think it's useful to experience other types of dance and other cultures, and the life of a classical dancer these days is certainly not all tutus! So experience of other dance forms is a good idea.
R. David Thomas