It should last 5 minutes!
My understanding of the question was:"How do I replace my existing topping lift line with a new one?".In my reply, which, admittedly, could have been clearer, I suggested butting the end of the old topping lift with the end of the new topping lift and holding them together with a tie wrap threaded through each of the lines. You can then use the old topping lift to pull the new one through the mast, over the block at the top of the mast and down to the deck. After the new line is in place, you cut the tie wrap to disconnect the old line.Fair winds,Tom