I think the majority of boaters with baby stays do not use them. On some boats such as my S2 9.1 which is primarly geared to racing they are used to induce more bend into the mast.
They also are used to stablize a mast that is "pumping" a lot while sailing into wave action. If you monitor your mast under these conditions and do not see a lot of "pumping" your rig should be OK in my opinion. If how ever you do see this then you probably should be using the baby stay at those times. Make sure your backstay is tensioned first as it will induce mast bend and which may stop the pumping.
Obviuosly continuous pumping will be hard on the rig and could lead to failure.
Last edited by Gary M; 09-25-2006 at 11:00 AM.