What do I have to check on every delivery, without being asked?

Front-foot and back-foot No balls: review the replay of the bowler's feet landing on every ball. It's a No ball if the back foot doesn't land within, and not touching, the return crease, or if no part of the front foot (grounded or raised) lands behind the popping crease on the correct side of the line between the middle stumps. Tell the bowler's end umpire immediately; they call and signal No ball. Because you've already done this, every later referral or review assumes the feet have been checked.

Other deliveries you rule on when they arise:

• High full tosses: a ball that passes, or would have passed, above waist height without pitching is referred to you by the on-field umpire; you relay the call and they signal No ball if appropriate.
• Short-pitched balls: only the second fast short-pitched ball in an over (above shoulder height) can be checked by you. Whether the first one counted is the on-field umpire's call.
• Any other No ball may be reviewed using the DRS technology. Wides can never be reviewed.

Also:

• Liaise with the scorers and tell the on-field umpires if an over has been miscounted.
• Every short run call can be reviewed on the on-field umpire's request.