A reaction point is delaying your decision as late as possible so that you have more information when making a decision

Setting reaction points is a concept I've wanted to write about since I frequently talk about it when reviewing vods for others. It's something I picked up from Druggedfox (go support him, he's super helpful and has put out a ton of good content on Youtube Patreon , and on his blog !)For Melee this would be making a decision 15 frames or so before you actually execute the option (for Ultimate it would roughly be about 17 frames). It's important to experiment and internalize that specific timing, and how that number is affected (reacting to multiple options, not reacting to the first frame of something, monitor lag, etc). This can be easily implemented during options that leave you unable to act for a while, such as rolling or spotdodging.For example an unstaled Chrom back roll takes 34 total frames, and you're invulnerable for frames 5-16. You can set a reaction point at about frame 17 (34 - 17 frames for reaction time = 17) so that you can make a good decision once you're able to act. If you had rolled and immediately decided to do something afterwards, you might make a terrible choice if you weren't taking into account what the opponent did during the first 17 frames of your roll (such as trying to attack when you should probably block the opponent trying to hit you).Since Chrom can be hit during frames 18-34, you should be reacting right at the start of the roll to check if you need to DI an incoming attack.Not having a reaction point set (or reacting in general) is why you'll see shit like people taking a split second to shield in neutral when they weren't even being threatened. They're using that moment to react to the current situation instead of doing that beforehand / planning ahead. Here are some other common examples of what it looks like when people aren't reacting properly--Missing a punish OoS because they didn't react to the opponent changing their aerial drift.-Picking a terrible option after something that lasted about 20 or so frames, such as swordie players dtilting twice in a row.-Bad combo/string follow ups due to not reacting to DI.-Doing a terrible option at the end of a dash.-No/bad changes to their drift during an aerial.-Not DIing a move properly after trying to attack (they assumed that it hit, so they stopped reacting).