Adhesions may form early on, but they can stiffen or toughen over time, leading to obstructions. Scar tissue can also lead to kinks and twists in the bowel, and of course stenosis (or narrowing) and stricture can also occur over time. Again, all of these things can contribute to blockages. I had several partial obstructions last year, although I was 6 years post takedown. Prior to that, I didn't have any issues. I typically will go to the hospital if I'm vomiting or in severe pain, or if the obstruction doesn't start to pass after about 12 hours. Thankfully I've been able to ride most of them out. I don't find the ER particularly helpful in any case, but I will go if I'm in distress. For me, adhesions and scar tissue around the old stoma site have been the culprit. I've made some modifications to my diet, which seems to have helped. I prefer to manage things conservatively and will only do surgery again as a last resort.