I wonder if you don’t get the same results from practicing sight-reading. I went back to some Naderman Sonatinas and such, and having them ringing in my ears after playing was almost torture. I don’t think any etude should be assigned if it isn’t worthwhile music. Damase has written some nice etudes, and I think we should get more serious composers to write etudes for the harp. Perhaps someone should organize such a project. I, for one, find them difficult to compose, though not exercises.
I had a similar experience when I finished my masters degree and began having to do office work. Without three hours to practice, I started to lose my sureness, and I didn’t have a maintenance regime developed. I went back to Miss Lawrence for lessons for several months, and I got right back on track. I have never found any exercises better than Salzedo’s Conditioning Exercises, just supplemental. I still use them as my basic daily routine, I just learned more ways to use them. For instance: I take one and play it in four different tempi. 16th = 60, 8th = 60, 1/4=60 , 1/2=60. This works great with number 1,2,3,10. Then I used to follow with orchestra parts, especially Tchaikovsky cadenzas, or Wagner. For years, I used the Magic Fire Music by Wagner. It really helps when you have auditions come up.