When I was a kid I had to practice Hanon finger exercises, some Czerny, and Alloys Schmitt for independence of the fingers, along with all scales and arpeggios major and minor in the Circle of 5ths plus the chromatic scale. Here are my thoughts:
Hanon, for the greater part is useless. The scale fingerings in Part III are in fact helpful when one is first learning them. Now, there is only one purpose for my resorting to Hanon. Maybe two or three times a year, for some unaccountable reason (maybe biorhythms out of synch), my playing seems ragged. To remedy that I open Part II of Hanon and play it through at about MM = 100, which only takes a little while. That medicine restores evenness. (Rachmaninoff preferred playing Scarlatti sonatas to regain evenness.) So that's the only application I use there.
The Schmitt (and Phillipp) independence exercises can be dangerous. My second artist-teacher gave me one simple independence exercise which works very well for both hands, and these days I rely on it occasionally when the need arises.
Pianists must know all scales and arpeggios by memory, major and harmonic minor for four octaves in parallel motion. (Harmonic minor is a better workout than melodic minor.) The reason is that scalar and arpeggiated passages occur quite often in music. If one already knows the standard fingerings, much time can be saved while practicing those passages.
Apart from scales and arpeggios, the other 99% of technique is developed by practicing actual repertoire pieces. Whenever the pianist works on a piece and encounters a difficulty, solving that difficulty through intelligent practice and repetitions becomes a "technical exercise" and most benefits the pianist. Thus, learning the literature of the piano is the best technique builder of all.
P.S. Egad! A third post on this! I must have been super-adamant about this subject!