I purchased a 10.5 foot telescoping ladder a few years back and use it quite a bit despite the fact that my trailer has a ladder on the back. I find the portable telescoping one much easier to climb and use. Mine has had quite a bit of use and still performs well to this day. I have never had a problem with it but it must be kept clean so it extends and collapses easily. The warnings posted above about smashing fingers when collapsing it are very valid. You must be careful when using it. I think if doing it over again I would get the 12 foot version so there is a bit more overlap at the top.
I keep it in the back of my truck which is usually loaded up when we go South for the winter. It takes up very little room.
You can see mine in use when I painted my roof
here. Scroll down to about the 7th or 8th picture.
Barney