Depends on how long you plan to stay out of your home country. If you're moving abroad semi-permanently/permanently, you'll want comprehensive international health insurance. You'll need the better benefits like cancer treatment and coverage for preexisting conditions as you get older.
You'll need to get on a plan before you get too old. Once you are insured, you can stay insured for life. But if you wait until you're older then you may not get accepted.
I use this company for my comprehensive international health insurance. They are founded by expats and focus on expats. They work with something like 50+ different insurers, so they'll always find you the best value policy with a reputable insurer that fits your budget.
****************************************************