What kind of fiddling do you do? As I noted, I've installed and removed hard drives, as well as switched video cards several times and had no issues. I started with an SSD and 1 HDD in this rig and now have 2 SSDs and 3 HDDs (and I've removed one HDD to move to another machine and replaced it with a bigger one in this machine). I can't recall if I've changed video cards 3 or 4 times, but it's at least 3 times. I've had no need to fiddle with RAM yet, but I wouldn't even hesitate if I felt I wanted to change/add RAM in my rig.

Pretty much anything in the guts of it. I'm not scared of putting in or taking out any of the components. I don't think this box will last as long as my last one (~7 years), given the relative cheapness of getting better mobo/CPUs nowadays.