Personal development for a member of a worship team should be a lifelong commitment. There's nothing worse than having team members who rest on their laurels and, in effect, leave it to the rest of the team to carry them.
Personal development obviously includes growing in understanding of your particular skill whether as a vocalist or an instrumentalist. But it's more than that.
If you were in a worldly band, you would be fulfilling a task that ultimately has very little or no eternal significance. But being a member of a praise and worship team, your work takes on a value that carries on into the next life. It is essentially spiritual in nature.
This means that worship team members have a respobsibility to grow in their walk with God, in their understanding of praise and worship, and in the depth of their spirituality.