Homework and chores kind of go hand in hand. They have to be accomplished every day. Our daughter started middle school this year, and she is exhausted when she gets home every day. I have a hard time putting her to work right when she gets home. Our initial rule was that her chores and homework had to be done before bedtime. That worked to a point, except that she was always underestimating how long it would take to get everything done and she'd save it all until the last minute. We then tried a different approach.
Our daughter gets home at 3:00 every day. Dinner's at about 6:00, and bed time is 9:30. That gives her approximately the same amount of free time before and after dinner. The new rule is that one thing (chores or homework) has to be done before dinner, and the other one after dinner. So far this has worked very well for us. She has a little time to relax after school and feels she has a little control over her own time.
Bed time has always been a problem at our house. We initially told our daughter she had to go to her bedroom at 9:30 but she could stay awake as long as she likes (reading, listening to music) as long as she got herself up when the alarm went off. This worked for a couple of weeks and then she started sleeping through her alarm. So now the lights go off by 10:00. As soon as she proves she can get up on her own again, she will earn this privilege back.
Social activities are great, as long as they're supervised by adults and also granted in moderation. Don't spoil your kids by letting them go wherever they want whenever they want, even if they have all their chores and homework done. The more time they spend with their friends, the more time they have to be influenced by who knows what kind of peer pressure. The more time kids spend at home with their families the better. Make social activities a privilege your children have to earn so they will see them as a privilege and not something you owe them. Teach them to spend their time in more constructive ways like reading, writing, or playing games with the family.
And along with the social activities comes phone privileges. Telephone conversations at our house are limited to 15 minutes each, 2 to 3 maximum per day, and not after 9:00 p.m. Even this is lenient, but it gives our daughter ample opportunity to talk to her friends about homework, etc. Limiting phone time also encourages kids to spend their time in more constructive ways and teaches them to think about what they want to say before they get on the phone.
Kids have a lot on their plates these days, and they aren't born knowing how to manage their time. This is where you come in. Kids neat to be taught these skills, and not just by word, but by example. Don't forget to practice what you preach.