Gary Boggs wrote:

After attending two high altitude chamber sessions and learning just how
diminished we are at even 8K, I use my O2 starting much lower than the FAA
requires. You don't use much when you are down low and some of us need all
the brain power we can get!

In our club, we have equipped all our ships with the EDS-D1 system.
(Each member brings his/her own cannula or mask, of course.) It has
become common practise to use the cannula for every cross country
flight. With the EDS system, the oxygen lasts forever.

It was an investment, but it feels good to wake up the day after an 8
hour flight at 9000 ft without a headache!

Stefan