Refill Frames

Refill frames refers to a mechanic that occurs at the end of dungeons when the game refills Link's hearts and magic meter. When this happens, the game takes real-time to fill Link's resources, and it will take longer the more depleted his hearts and/or magic are.

Mechanics

With hearts, the game will take 10 frames to refill each one that you're missing. It will even take 10 frames to fill hearts that are only half or quarter damaged.

With magic, the game will take 4 frames per 4 MP. When Link has a full magic meter, he has 128 MP. This means that if Link has no magic, it will take 128 frames for the game to refill his meter.

The game refills Link's hearts and magic concurrently. This means that the net time loss is exclusively determined by whichever resource takes longer to refill. So for example, if the game needs to refill 3 hearts and 48 MP of magic, then you'll face a 48 frame refill. The 48 frames to fill 48 MP beat the 30 frames to fill 3 hearts.

Implications

The key obvious implication to this mechanic is that taking extra damage and using extra magic are both generally bad. However, because the refills happen concurrently, you won't always lose time to refill frames when taking damage or using magic. One example of this is during the Eastern Palace segment of the Any% NMG run, the player will have either very low or no magic after beating the dungeon. This is just because of how you start the game with no magic. As a result of this, your heart refill doesn't matter, and any extra damage won't impact your refill frames.

Another implication is that strats that take intentional damage or use extra magic need to be weighed against their refill cost. If a strat saves 10 frames in a room but uses an extra 16 MP in a segment where magic refill is relevant, then the strat doesn't actually save any time.