Safety Altitude

I always flying with 0m in the computer. Safety margin has to be adopted by local and weather conditions. Headwind, tailwind, terrain etc has to be taken into account every final glide.

In typical flatland conditions with evenly distributed Cu and no convergences is my tactics to have about +200-250m on actual Mc-value about 30-50km out. The closer I get to the airfield the lower margin can I accept as there is a smaller chance of getting in trouble, ideally do I have +50m 3km out to make straight in landing if applicable. As I’m flying an unloaded club class glider do I always have the option to burn out the extra energy by push the stick forward if I get to high �
On the other hand, flying in mountains with a ridge could easily get you home when you are -200m 20-30km out, the same goes for strong convergences.
I also tend to have more margin in tailwind than headwind situations, more than once have the tailwind decreased rapidly with height. A typical scenario is that you are +200m with strong tailwind at 1500m, after a few minutes glide are you at 1000m and the tailwind is now Zero. When the computer recalculates the final glide is all your margin gone, you are low and its late in the afternoon. An close to home outlanding is inevitable…

Therefore is it pointless to have an preset safety margin, it has to be set according to current situation.