Whilst oxygen is compulsory above 10,000 ft QNH, it would be better to use it above 8,000 ft if flying above this altitude for some time. This is because our type of flying is a lot more physical than other forms of aviation and is usually combined with heat, mental, environmental and competition stress. Accelerated fatigue, tiredness, reduced mental alertness and headaches are the symptoms of prolonged exposure to reduced oxygen use. All these effects are initiated through lower oxygenated blood levels to the brain and can be damaging to the brain! Be wary of convincing yourself that you can handle 10-12,000 ft continuously because you are fit or used to it! To test yourself, borrow an Oxy system and take a sniff after exposure for a while at 8,000 ft. It is very likely that you will experience a clearing of the head and any energy level increase. I feel it is unfortunate that we do not use oxygen a lot more in our gliding in Australia and believe that we should have it at competitions for safety reasons and use above 8,000 ft QNH.
Aviation Oxygen refills (to about 3,000PSI for about $30, Mountain High systems no problem) are available through:
Unit 5 25 Beveridge Dr
Tullamarine, Vic, 3043
Phone: 93381253 040918801