Okay, so I realize that he had to regenerate during the sixth season, but I recently saw the seventh season episode "Imperfection". Inwhich Seven's Cordical Implant malfuntions, and because it's broken she can't regenerate. Well to save her, Icheb gives her his implant. You can go on Memory Alpha to learn more about the episode or just watch it.
Now he's surviving without an implant, so does he need to regenerate anymore? Because it seems that it's essential for regeneration.
We don't see too much of Icheb after this, I don't believe, but, I seem to recall at least one time, I would've expected to see him Regenerating alongside her, and he was nowhere in sight, so, yea maybe, it was no longer necessary
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?