Sometimes I use the wall when doing a) standing poses and b) balancing poses. I think the wall is a wonderful prop, but not if you use it all the time.
Examples of times to use the wall:
- Some early morning and I feel just on the edge of dizzy. Often if I use the wall for the first time through the pose, then I gain some stability and move away from the wall.
- When I was sick last year I gave myself permission to use the wall all the time. My joints were too immobile for me to steady myself.
- If I want to work on some particular aspect of a pose where I don’t want to worry about falling over, I’ll do it at the wall. This works well for me for Parsvottanasana (intense side stretch) and Virabhadrasana I, where I can’t get my heel to the ground.
I have to say, though, that I always think about it in a judgmental way and have to have a little conversation with myself about it.
“You are such a baby, wussing out and going to the wall.”
“I have good reasons today. I want to get the big stretch of Ardha Chandrasana without worrying about falling over.”
“Well, OK for this time, but don’t get dependent on it.”
“I won’t, I promise.”
And if I DID need to do it all the time, it wouldn’t make me a bad person.
Boy, this post sure falls into the self-talk category!
Practice Notes 
Parsvottanasana is always a challenge for me. I found that Leeann Carey has a great free yoga video that shows what to look for in the pose so it doesn’t seem so straining. I thought your readers might want to check it out: http://planetyoga.com/yoga-blogs/index.php/free-yoga-video-parsvottansana-what-to-look-for/