The Casio F91W, traditionally a simple and economical watch, has garnered a lot of attention for its modifiability and performance under extreme conditions. Users have successfully customized the watch with programmable microcontrollers, modified its functionality by oil-filling to enhance water resistance and visibility, and even adapted it to display tide levels. Such hacks showcase a vibrant community of watch enthusiasts who explore the limits of this affordable timepiece, pushing it into realms not originally intended by the manufacturer. Casio has also released variants of the watch for the modding community. However, potential modders should be cautious of drawbacks like overheating in sunlight or possible feature malfunctions.