But you rarely get it wrong once you've learnt to glide
Without trying to sound smug, also not "really" disputing what SB says,
but I've never yet had to throw away an approach into a licenced airfield due to getting it wrong (the landings haven't always been perfect mind you
) I have gone around a couple of times when going into strips ... but then you are pushing the limits and would expect to not always get it right. Any glider pilot worth his/her salt would go around in such circumstances, but the get-down-itis of a glider pilot is really a non-issue!
SS
PS. BTW, you can only count hours in a SLMG/TMG if you have a valid TMG rating on your SEP licence.