I run 4 miles in the am then 30 minutes kickboxing and 1 hour of lifting at night. how many days can i do this before needing a day of rest?

6 days but: You really should only weight lift every other day, or you won't get as much benefit and more likely to get injured. When you stress your muscles, you actually make tiny tears in the muscle fibers and when they heal, they get stronger. You can do aerobic exercise every day, but it's better to mix it up, or else take one or two days off a week to rest. Alternate run/bike for example.