To keep extensions secure throughout the day, make sure to fasten them tightly to your natural hair. For clip-in extensions, section your hair and clip them close to the roots to prevent slipping. For other types like tape-ins, ensure they are professionally installed by a qualified hairdresser or hairstylist. You can also add a bit of dry shampoo or texture spray to your roots for extra grip. Finishing with a light mist of hairspray can help hold both your natural hair and extensions in place for longer-lasting wear.