It is very difficult to predict shelf life of such solutions as it depends on many factors - temperature, material of the bottle, purity of water used to prepare the solution and so on.
As far as I am aware commercial bleach has pH increased by added NaOH, that makes the solution more stable and substantially slows down hypochlorite decomposition. When you dissolve the calcium hypochlorite there is no additional raise of the pH and teh decomposition starts immediately. That still means it should probably work OK for several days.
When left open these solutions will slowly release chlorine and absorb CO2, in the end you will be left with just carbonates.