How long should i practice my saxophone for?

i practice for 30 minutes, is that enough?

I think the best way to practice is to set a goal for each practice session then practice until you reach that goal or come closer to reaching the goal. This could be 15 min or 45 min or an hour and a half. For example, I just auditioned for college scholarships, and in my practice, I would warm up, then think about something (dynamics, tempo, articulation etc) that needed some work. I would practice until I got tired or until I felt that I had improved at least somewhat. Try not to limit yourself exclusively to a time.

Yes, thats a perfect amount as long as it is daily or for the majority of a week

Well, I guess it depends on what you want. If you want to be excellent, then you should practice whenever you can. If you want to be just alright, then you should limit the amount of time you spend. It comes down to priorities, I guess. When deciding how to spend your free time, ask yourself, "which is more important: that become a better player or that I ... (read a book, watch TV, make out with so and so)?"
If playing is really important to you, you'll make time for it. ^_^

It depends on how good you want to get at it. 30 minutes is ok if you want to play for fun and learning. Try an hour and see how you feel. Professional musicians practiced sometimes 2 or more hours as younger players and graduated to many more hours as adults.

30 minutes is a good amount of time to practice if you do it consecutively every day. Sometimes us musicians just don't have a lot of time to practice. The key to becoming a better player is to play everyday (or as close to it as you can). But when you do have time (summer or weekends) you can play for hours. Charlie Parker used to play 15 hours a day. I, myself, have a record of playing for 6 hours straight. It gets boring, your lip gets worn out, and you start to get tired. I'd recommend starting with 30 mins a day and working up to and hour or 2 hours a day. If you can't spend an hour or two one day then just play for 5 mins. It's better to play 5 mins one day and and hour the next than to play an hour and five mins one day. Good luck.

usually for 30 minutes a day but start out with 15 minutes

You'll probably hear this alot, but really it depends on what goals you have for yourself as a player. 30 minutes a day is a good amount if you practice every day consecutively. Basically it all comes down to; practice makes perfect! In other words, the more you practice, the better a player you will become! I don't know what kind of band you are in or if you are even in a band, but I'm in a high school band. I can just imagine if I had been practicing earlier this year as much as I have been lately, that I could have easily had a much better marching season!
Hope this helps!
Good Luck and God Bless

It depends. Are you on task? You can practice for 30min. and only TRULY practice for 10min.

If you are on task that is a good amount to practice.