See my reply to s800.

Before you jump ship to precision tests of gravity: graduate students' mean time to graduation in our group is >7-8 years. Our experiments take several years to set up, at least a year to execute, and at least a year to analyze.

When a new idea/theory comes up, we can often test it quickly (or rule it out with existing measurements), but our bread-and-butter work is a direct confrontation with hard experimental problems.

For scale, we can choose to be separately sensitive to both the gravitational signal and the tilt of the ground due to a pickup truck parked outside of our lab.