Noise limit should work fine if the complexity of the scene is uniform across all frames. If that's not the case, e.g. if camera moves from a room with furniture, to exterior where only one tree is growing, seen against a bright background, then the quality may vary. This is something the dev team is aware of, and, despite the fact that everything is working as intended, we are planning to improve this in the future releases.
The safest solution is using the pass limit. You do not know how many of them is required, but one way to tell it is rendering one frame. If you decide that the quality is too low, instead of re-rendering the image with a higher pass limit, you can just use the "continue rendering" option, and give it a few more passes. All of this might be a bit confusing at the beginning, if you have never dealt with a progressive renderer before, but once you get the hang of it, it becomes super simple. That's why we have so many amazing renders in the gallery. :)