[james_marks]

If the argument for NoSQL is, “we don’t know what our schema is going to be”, stop.

Stop and go ask more questions until you have a better understanding of the problem.

[jampekka]

Oftentimes better understanding of the problem needs trying out solutions. Armchair architectures tend to blow up in contact with reality.

[freedomben]

For sure, though with databases it's usually pretty clear even at the start whether your "objects" will be relational in nature. I can't think of a single time that hasn't been the case, over hundreds of apps/services I've been part of. Things like asynchronous jobs, message queues, even object storage, I fully agree though.

[ranger_danger]

Even a JSON column would be better in most cases IMO, and on Postgres you can also make indexes on json keys.