Benchers hold office for life once elected. A bencher can be elected while still a barrister (usually, but not always, King's Counsel in the UK or Senior Counsel in Ireland), in recognition of the contribution that the barrister has made to the life of the Inn or to the law.
Benchers serve as lifetime members of the bar association once they are elected.  A bencher can be chosen while still a barrister, typically a King's Counsel in the UK or Senior Counsel in Ireland, for their contributions to the bar association and the legal profession.