Automatically cancels a Will unless it had expressly been made in contemplation of that marriage. Any children by a previous marriage or relationship can only be provided for by a new will.

Does not affect a Will but it is sensible to consider a new will at that time.

Provisions for a former spouse are automatically cancelled but the remainder of the will is still valid but should be reviewed.

May have changed. Your estate may have increased and be liable to Inheritance Tax which could be reduced by a new will.

If you have disposed of any asset mentioned in a will then the gift is of no effect.