Your miles are to be used and enjoyed. A business class award to South Africa is a big win for you. Stored up miles don't do you any good, and stored up points or miles can actually depreciate over time. (Hotel chains, for example, frequently raise the number of points needed to redeem a room.)

Take the cost of the coach ticket and divide by 40,000. That will give you the cents per mile value you are getting for redeeming 40K miles for a coach seat.

Then take the cost of the business class ticket and divide by 60,000. You will likely see that the cents per mile you are getting on the business class seat is far greater than the coach seat. If so, redeem your miles in business and look forward to enjoying your flight - that's a great redemption.

Stick around FlyerTalk. You'll soon be learning lots of ways to replenish those miles you've used.