Young Trumpeter

Hi i'm in high school, studying to major in music, and i have a question i need answered. my band teacher (a trumpet player) says i need to put in hours and hours and hours of practice time. my private teacher says that what matters more is what i do with the time i practice, as opposed to how much time i spend practicing (of course a reasonable time is assumed, not 20 min a day or something). as much as i love trumpet, and as much as i want to be a freak, i would also like a social life. plus, i find that my lips can only go for X amount of time and i just don't have the endurance to practice for hours and hours a day. also, when i'm not literally practicing trumpet, i'm doing music-related things, such as listening to pros, reading on forums like this, ear training, etc.

so which is better?

Thanks,
Aaron