5 uncles, and none of my 17 male adult cousins in the Netherlands have had problems. My 3 year old had a "problem" last year - he was playing with it and there was discharge (smelly) the doc thought it was infection - it was gone that afternoon and we never did anything for it - I've read that happens and is normal.....
I don't have sons, but my dh is intact. He is not able to retract very well (phimosis) and it causes him some pain and his glans is overly sensitive because it never comes out of hiding. He retracted the first time in his life the first time we had intercourse (his first time). He had to stretch it in the shower but as long as he does that regularly, it will retract. If he doesn't do it for awhile it gets tight again.
He and I passed a yeast infection back and forth once. I could not figure out why I kept getting infected after I treated myself. Finally dh retracted and there was the infection. He treated himself with OTC cream and was fine after that. I am guessing that an intact man could more easily harbor a yeast infection.
That's pretty much it. Both things we consider minor, and dh would have wholeheartedly not circed any sons he had because he doesn't think it's right.
Almost 6 years old. (Not potty trained due to developmental delays, nothing to do with foreskin) Yeast infection about 6 months old. Feared that because we lived in a "high-circ" area, the doc would tell us it "needed" to be done. Gave us a script for Nystatin and monistat. Cleared up and no problems since.
I have a 20 year old, 17 year old, 15 year old, 10 year old and 6 year old brother. All intact. No problems. Most of them voluntarily retracted in the bathtub before 4 years. They all learned how to clean themselves...just like all little children learn how to blow their noses and wash their hands.
My intact DS once got a swollen penis when I forgot to change his dipe during our house move. (He used to change it himself but he forgot too!) He spent a couple of hours diaperless and that was the end of that drama.