Plan daily music practice around goals.
A practice schedule is a weekly goal divided by practice days, then allocated across the three things that need attention: technique, repertoire and sight reading. Fixing the shares in advance prevents the usual drift, where the piece you enjoy absorbs the whole session and scales and reading quietly disappear. Repertoire takes whatever the other two leave, which keeps the allocation internally consistent.
Daily budget
Daily minutes = weekly practice goal hours x 60 / practice days per week
Allocation
Technique = daily x technique share; sight reading = daily x sight share; repertoire = remainder
Yes for motor learning. Six thirty-five minute sessions produce more durable technique than one three-and-a-half hour session, because consolidation happens between sessions rather than within them.
Twenty to thirty-five percent is a common range, weighted higher when working through a technical barrier and lower when preparing repertoire for performance.