How long are your routines? Do you have a consistent format and structure for competitive pieces (solos, duos/trios, groups, lines) and recital/concert routines?
I operate by the philosophy- less is more. Leave the audience wanting more!
Sometimes, it seems as though we, as an industry, feel burdened to the time standards set forth by competitions, etc. You know what is best for your students and, in determining their music length, you should consider their (1) stamina, (2) technical vocabulary, and (3) presence (how long can the student hold the stage and connect with the audience)?
As a general standard, for competition routines, I utilize the following lengths of time:
Solos- 1:50-2:05 minutes
Duos/Trios: 1:50-2:10 minutes
Groups: 2:00-2:20 minutes
For recital routines, our younger students perform between 1:50-2:00 minutes and our older students perform between 2:00-2:20 minutes.