Barring genetic susceptibility to issues above and beyond the "normal" we have to remember that even long term there is a huge difference between use and abuse.
Even blasting and cruising isn't abuse if your "cruise" is time on = time off and the cruise dose keeps your test levels in a reasonable range (around 1000ng/dl)
Bloods are a must. I will be taking an extended break after this summer because my bilirubin(bile secreted by the liver when RBC are broken down) is elevated. Not a bunch. But it still is. There are many reasons this could be the case. There are even positive side effects to having elevated levels believe it or not. But I want it to come back down.
People don't get medically involved enough when they use AAS. As Steve mentioned. Lipids are a huge thing. I myself go one step further. Every other year or so I get an echocardiogram(working ultrasound of the heart). That measures size, close estimate of weight, valve sizes and timing, blood flow through chambers, ventricle size, LVH ect... Just had one done a couple months ago and I was pleased it came back perfect.
I even got an abdominal ultrasound done a couple weeks ago just to make sure I didn't have any gallbladder issues (due to the elevated bilirubin) or gallstones. But it also checks the liver, kidneys ect...
You cant be too cautious. Most guys don't even do bloods let alone anything further.
Always take a lipid supplement when on AAS. Whether you need it or not. That's my philosophy. Either N2Guard or Lipid Stabil. They both work.