Capture once to use up a threat

If you have first capture in a ko fight, it may be correct to capture the ko once even if you will end up losing the fight. The fight may be unfightable, in principle; and you may have to concede the fight by making a defensive play immediately when your opponent recaptures in the ko. Still, you will have made some use of the position, since your opponent will have used up a single threat (which is normally a small loss, for example of some aji, and if nothing else, leaves them with one less ko threat for the next ko fight).

Bill: Forget the once and only once. It may be correct to capture the ko many times. Not only may you use up ko threats, and gain from that in regard to other possible kos, you may gain more in exchange for losing the ko by forcing your opponent to win the ko before he might otherwise have to. In some cases, you might even win the ko, because your opponent does better to let you. (I call that tunneling.)