I agree, and in general I am very pro-estimates (they switch your team from cooperative scheduling to preemptive scheduling, and they’re an important tool for m

I agree, and in general I am very pro-estimates (they switch your team from cooperative scheduling to preemptive scheduling, and they’re an important tool for managing the chaos of development), but the statement “we expect this project to take eight weeks, but it could take 24 weeks in the worst case” is one I would be very loathe to make. Granted, I’m coming from a B2B startup rather than a consultancy, so I was working with a mixture of internal (product, sales, support) and external (customers) stakeholders. The perspective I would try to give people, though, was this: If we discover a bomb partway through the project (oops, groups are limited to 100 members in this auth system, so we will need to find a new system and migrate or else not support groups) then 8 weeks will no longer be enough, but maybe neither is 24. The right thing for us to do in that situation, IMO, is go back to the stakeholders and align on a new plan. Maybe groups will come in v2, or some groups will work and some won’t, or maybe we do the migration and add it to the estimate, or whatever. One shouldn’t use the 16 buffer weeks between 8 and 24 to sneak in a backend migration (which itself might be a 16-week project, or might not), but to pause and re-align on a plan everyone likes. When I was giving estimates, I would try to frame them as “we’ll spend eight weeks trying to accomplish this list of things. If we discover an issue that prevents us from finishing the list for any reason, we’ll come back to you as early as possible with some alternative proposals and re-assess”. Sometimes people felt that this meant we just weren’t willing to commit to our estimates, and this idea of “software development is chaotic” is what I would say, to explain that the issue wasn’t a lack of motivation, but an inescapable knowledge risk that needed to be managed.