The formwork decides, not the concrete
The finished surface copies the formwork. System formwork with smooth panels gives an even surface, while old, reused boards leave grain marks and unevenness.
The layout of joints and tie holes is part of the architectural design. If it isn't planned in advance, it ends up random, and on an exposed wall that stays visible forever.
The pour can't be repeated
The concrete has to be placed continuously and compacted evenly. Interrupting the pour creates a visible construction joint that can never be removed.
That is why weather, the availability of the pump and whether the team is used to working under time pressure all matter with exposed concrete.
Allow for tolerances
Exposed concrete is a natural material. Slight differences in shade and small pores are part of it and are not defects. They are exactly what gives it its character.
If you expect a perfectly uniform surface without any texture, plaster or cladding is the better choice.
