Just playing devil's advocate: * People don't work effectively for 40 hours every week 100% of the time. Perhaps 2 people working 20 hours allows greater utili

Just playing devil's advocate: * People don't work effectively for 40 hours every week 100% of the time. Perhaps 2 people working 20 hours allows greater utilization of the time with less waste because each person is fresh for greater parts of the work week. (We'd need multiple well designed studies and attempts to find the right amount of time). * All the onboarding and upfront costs you mentioned are legitimate, but small in the grand scheme of things. Once onboarded, hopefully they are creating value. Two people onboarding together could also take some of the load off a mentor as they could help each other. * Not all engineers are equivalent. Some might have a ton of database experience, another could be more ops oriented, and a third might have great algorithmic thinking. All can be good engineers for the role. But if you had 2 or all 3 then maybe the increased diversity of experience and skills can make the work progress faster with a higher quality. * More people meaning more communication channels is a real concern. It's also something you have to deal with at some point. Management in general is about finding ways to work efficiently, and just like any other scenario you'd take this one into account when deciding how to work. Figure out smaller specializations, or chunk work in ways that compliment the team, or structure documentation/ideas/communication in a way that can be picked up by others.