Did you know that recent research shows that the 30 minutes of exercise that is recommended each day does NOT have to be continuous? You can split that time up, so you could do 15 minutes in the morning and 15 minutes in the evening. (for example) Isn't that great news??!!
If you do split your workout, just be sure to warm up and cool down each time and this pretty much eliminates the "i don't have time" excuse!
So, make a plan that works into your schedule and do it!