Hmmm, I am going to disagree with a few people here.
I have hunted out of homemade treestands on my own property for 12 years now. I have yet to fall (obviously), have a part fail, or have anything else bad happen. (Note me knocking on wood here). Alot of it is inspection and maintainence. I am constantly looking over my stands, and if something dont look right the part is replaced or the whole stand is rebuilt. Time consuming, you bet. Money consuming, no doubt. But there is something really satisfying about building your own stand, especially when it is huge, contains three trees, and can seat three people.
A ladder stand I have never built, all of mine are supported by, well, I dont know the technical term for them, but they are beefy. I use the biggest nails possible, and make sure that the pressure treated lumber is not comprimised in any way. Just gotta make sure you do things right!