Agreed, but in practice, I think needing to wait for sprint planning is very time-wasting and in practice not efficient. If a dev has worked 3 days in the wrong

Agreed, but in practice, I think needing to wait for sprint planning is very time-wasting and in practice not efficient. If a dev has worked 3 days in the wrong direction, they will naturally try to salvage some of the bad things, or even try to pretend that their solution is "the only way". It can be negotiated, with more or less success, but the negotiation itself is a waste of time if it could have been caught earlier. 100% agree with planning the meeting to avoid flow interruption. It's strange to see so many people here saying that you can just "ask whenever" when the argument about avoiding interruption is brought so often.