What is the difference between Tricare and CHAMPVA?

Tricare is for active duty military and their dependents.  It is a Department of Defense (DOD) benefit.

Tricare for Life is for retired military veterans (20 years of service or more), their dependents and for surviving spouses of soldiers killed in action.  It is also a DOD benefit, but administered through a private company.

CHAMPVA is a VA benefit for dependents of living veterans rated 100%, for dependents of veterans who died service connected, and for dependents of veterans who were 100% rated when they died.  If you are eligible for both, Tricare for Life, is the benefit of choice, as you cannot have both.

Both cover health benefits. 

However, parents are not eligible for any of the above.