I've known a total of 4 musicians who practice like we think a musician should - that is, 4 to 10 hours a day forever (3 of them have spouses with lucrative jobs to support them). But what the normal excellent musician does is grabs practice time whenever they can, an hour here, 2 hours there. And there are days, weeks, even months when they don't practice, can't practice. So grab your practice time when you can and hang in there. Don't get discouraged when you miss a day or a week and give up. Keep working and growing and you'll make it.
It's very important to push yourself and try hard pieces, fast tempos, high notes - extremes. It pulls your abilities forward.