I have no vices. 我没沾染上恶习。
Old habits die hard. 积习难改。
Sleeping pills can be very addictive. 服用安眠药丸容易上瘾。 Habits often become second nature. ;习惯常变成第二天性。 You've got to help me break this bad habit. 你非得帮我去掉这坏习惯不可。