HOW HIGH TO FLY? A safety tip -
Power pilots reading this, please take into account that on a good day for gliding, there will be A HECK OF A LOT OF GLIDERS and not always near gliding sites. They can be found between 500' and cloud base. (lower than five hundred feet they get nervous and look for a field)
So if you want to be safer, if at all possible, on a good day for gliding, plan your flight above the tops of the cumulus. Avoid the crowd. As well, it will be a smoother ride altogether.
If you are a non-smoker, you should be quite comfortable up to 12,000.