I believe in scales everyday. Most concerts pianists and great pedagogues will say the same.
I have a system that I use on a regular basis:
1. Scales in every major and minor (harmonic only) key, four octaves: Unison, thirds, sixths, and tenths. Then, contrary motion in thirds, sixths, and tenths.
15 minutes
2. I have a 5 minute non-repetitive chromatic scale exercise. It is four octaves and uses both contrary and parallel motion.
3. Double thirds in every major and minor key, four octaves. I play these twice, once legato and once staccato. 10 minutes.
4. Arpeggios in every major and minor key, four octaves in all inversions. I play these twice though also, in triplets and quadruplets. 7-8 minutes
5. I have a creative octave regimen that allows me to build up stamina and gives me adequate periods of rest. 15-30 minutes depending on whether I do the whole program.
So, in total it takes me an hour to do everything I need to do technically.
I never used hanon, czerny, or any series of exercises. I don't believe they are necessary. I did however play through the Chopin etudes everyday for about three years. That helped.
I don;t know anyone who is any good who hasn't slaved over scales. I am seeing more and more threads that deal with trying to find an "easy" way out of playing scales and practicing a fair amount of technique. I don't practice scales that much anymore, but the years I spent doing them really made the difference.

If one is playing for fun and enjoyment only, then 10 minutes a day is fine. If one is planning on a career, then hours must be spent on scales. Many teachers don't insist on them because they are afraid they will lose the student. There is no substitute.
Robert Henry