1) If you're in a hurry, you can start lighter in your routine or program and warm-up and stretch that way.
2) The more intense the exercise or sport, the more necessary a warm-up becomes. For example, you don't need to warm-up and stretch before you go for a walk but you do before a basketball game.
3) The main focus should be specificity. This is a fancy word for warming up and stretching the muscles and joints specific to the activity you will be performing.
Sample Warm-Up: Light Activity like Cycling, then 10 each of Arm Circles, Weight Shifts left and Right, Toe Touches, Push - Ups, Jumping Jacks, Squats, Lunges, and then 30 seconds of Downward Dog and Upward Dog.
Sample Stretching: 5-8 Stretches targeting both 1) Areas you are in need of flexibility 2) Areas which are most engaged in the work you'll be doing.
The goals of warming-up and stretching are 1) Prevent Injury 2) Perform / Train better 3) Engage the mind and prepare to focus 4) Improve muscle imbalances, tightness and facilitate injury recovery.
More advanced stretching exercises can be used to address specific movement problems and injuries.
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