How long do they last?

[Duckhot16]

So I'm looking at buying a set up yurt on land. It's been there for about 4 years and lived in full time. The winters aren't too harsh in NC but I noticed that the velcro for the windows and the zippers are already starting to fall apart on thier Colorado Yurt. My question is how does one change out the wall fabric with out having to tear everything down? And also how long has someone actually lived in theirs full time before they needed to do major replacements like wall and roof?
I'm just really on the fence because I don't think they took as good of care of it as they "should" have so I just wanna know how long till were gonna have to replace the big parts.

Someone with first hand experience please help me with this!!!!
Thank you