Input from another two Senior Toolpushers working for the same Drilling Co, but different clients:
1. Well that is a tricky one. If the client cannot be negotiated with, it should be every 10 joints. Most will agree that for efficiency once after connecting the double and splashing the BOP again at the halfway point, again before picking up the slip joint, then after connection of tension ring. Then Land the BOP test the connector once per well after landing stack.
I usually try and get agreement that doing less test as long as the riser is in good shape. We also have to agree that there will be no down time rate applied if there is a leak while we find it. .
2. While running riser the connection is tested after BOP is under splash zone 2 joints and then every 10 joints, and of course at the last connection.