> "I cannot estimate Z" is a refusal and I would suggest an ego-driven one. This might come down to a cultural difference or difference in communication styles

> "I cannot estimate Z" is a refusal and I would suggest an ego-driven one. This might come down to a cultural difference or difference in communication styles. As an IC, I'd consider it to be much more honest on my part to be upfront about unknown timelines instead of providing a (quite frankly, useless) estimate just because it's what my manager wants to hear. At the end of the day, the work will take as long as it takes (managerial interference aside), and I believe in underpromising and overdelivering, precisely to avoid situations where someone's on the hook for an estimate that didn't pan out. If I wanted my business to be making accurate projections, I'd have been a quant.