Here is a good reader question: “When is it acceptable to overrule your partner? For me I back up my partner on all calls, unless he asked for a second look. I feel it is better for the team and the last thing I want to do is make him feel like crap. Naturally, if there are constant egregious mistakes, I might look on it differently but that rarely happens.”
Sorry, I am on the other side of that issue. I feel you should check the mark on every close call and/or overrule immediately during a point, if you think your partner has made a wrong call.
Some people will argue, that having a good doubles relationship dictates “going along” with an occasional mistake; but I believe making the correct call is the only fair thing to do.
A solid 98 out of 100 guys we play with do not intentionally make bad calls; and welcome (accept) the correction. For the other two guys, I would then choose not to play with them.