How level and plumb can plastering be

[Millwright]

So, how level is it reasonably expected to have a plastered finished wall?

If I put a two metre level up against a wall, vertically, should it sit flat? Is it reasonable or not to expect a slight deviation or curvature?

 

[roughcaster]

Nothing will ever be 100%, but a plastered (float and set wall), done by somone who knows what he's doing, should NOT be far off. The very same as an expert builder, building level and plumb.