M_Boats: topping lift question

Hi all. I'm a new owner of an 1981 M17. Works great. But I have a question about a topping lift. Should I have one? It is currently rigged without, but that is because I just rigged it the way the previous owner rigged the mast. Seems to me there is no reason not to have one. It would certainly keep the boom up when lowering and reefing the main. Am I right? -tom