Maybe set some alerts on google flights? I have been watching south/southeast Africa fares for a few months and *A airlines seem to have quite a few deals that pop up for a day or three. Especially to DAR. As an example, they were around $600/650 from SFO a couple weeks ago and have seen them around $750 from AUS - off and on. [In Y] Most flights where United to either the east cost or somewhere in Europe before connecting to a *A Africa airline - which would earn MM credit for the United portion and come in at under $1000