I have a 7 foot Stokes aluminum tripod, nearly 10 years old. It appears
to be practically indestructible and can be left in the orchard over
winter, but they are not cheap. A 7 footer would be about $100 today,
and they go up from there. I sometimes wish it were a 9 footer, but not
very often, since the shorter model is much easier to lug around and set up.
Safety consists of rotating the ladder if it is on a sloping or uneven
surface until it is vertical and stable, and avoiding lateral forces
when you are on a high step. I sometimes go to the top if I have
something to hold on to for balance. It is always possible to achieve
good stability with these ladders. There is really no comparison
between these things and a standard, four point stepladder. Stokes is
located at Kelseyville, California, but I was able to find one locally
at Winchester, VA, where some commercial processing apples are still grown.