The time it takes to re-dye bleached hair depends on several factors, including the type of dye you are using, the extent of the coverage needed, and the condition of your hair post-bleaching. Here's a general breakdown:

1. Application Time: If you're just touching up or refreshing the color, and the dye is an all-over color application, the process itself typically takes around 30 minutes to an hour once the dye is mixed and applied to the hair. This includes the processing time required for the dye to develop, which is usually indicated on the product instructions and can range from 20 to 45 minutes.
2. Prep Time: Before dyeing, you might need to spend time preparing your hair. This could include washing your hair (if it isn't freshly bleached), detangling, and sectioning it for even coverage. Additionally, if your hair is very porous or damaged from bleaching, you might want to apply a deep conditioning treatment prior to dyeing to improve the hair's condition and ability to hold color.
3. Condition of Bleached Hair: If your hair is severely damaged from bleaching, it might absorb color more quickly, possibly requiring less processing time. However, damaged hair can also react unpredictably to dye, sometimes grabbing color unevenly, which might necessitate extra care and attention during application.
4. Type of Dye: Semi-permanent or demi-permanent dyes might take less time to process compared to permanent hair color. Additionally, if you're using a direct dye or a toner to neutralize unwanted brassiness, these may require less processing time.

In summary, while the actual application and processing time for dyeing bleached hair can be anywhere from 30 minutes to an hour, taking into account preparation and the unique needs of your hair, the entire process can take longer. Always read and follow the manufacturer's instructions for the specific dye product you're using and consider consulting a professional stylist for the best results, especially if your hair is fragile from bleaching.