How do you choose which churches to look after?

We don't. The Church Commissioners, with advice from a separate expert committee, decide which churches no longer needed for regular parish worship are so historically or architecturally important that they deserve to be preserved on their own merits. Normally - but not necessarily - churches graded as I or II* listed buildings come to the Trust. We have the right to make comments about any proposed church before a decision is made, but in the end we have a duty to care for all churches 'vested' in us.