If I am not free from malfunction by 2,500, I am chopping and hoping that my reserve is a square, stable and steerable canopy.
I look at it this way...if I cut away lower than that I may end up getting hurt or worse due to obstacles. I want time to at least think of a landing location and pattern.
Every one has a different opinion and set of altitudes, but hell I have just over a hundred jumps, so what the he!! do I know. You will never be more alive than you are the instant you let go!