Often, when Hiro re-appears at Ando's side, little or no time has passed for the guy that digs Hiro's sister, yet weeks, even months have been lived by Hiro. At the Burnt Toast Diner, a day or two after leaving, Hiro had spent 6 months with Charlie, and even more afterwards as he leapt forward and back again and again to try and save her. Every instance he stops time for everyone else, Hiro is still in motion, so will this begin to be addressed by the writers, perhaps showing some new wrinkles or gray hairs if that behavior continues, or is Hiro somehow protected from the ravages of time because of his gift when he travels?

It would take years (Hiro-time, not necessarily real time) before he aged sufficiently to be obvious. (He's ...not quite 30 when S1 starts?)

I'm fairly certain that one of the BTE interviews commented that 6 months is 6 months for Hiro, no matter "when" he ages those 6 months. So, I would assume it'll be dealt with eventually.

In reality, Hiro would have aged as many seconds, minutes, hours, days or years whenever else he is in time when he returns to the present. It still is a tough concept to explain, though.

Will he show it? Maybe, maybe not. Like I said, it'll take a while before there's a noticeable difference.

However, in answer to the question:


Source: http://www.comicbookresources.com/?page=article&id=9484

Don't forget that he also loses time, like the four months between stabbing Sylar and coming back from 1671.

If Hiro had a little better handle on his leaps through time he could have just returned to the present mere seconds after he had disappeared, but considering this was his first real dramatic leap through time (400 years into the past) he still needs to learn how to handle navigating such a time gap.

It appears time jumps through shorter gaps of time, whether it be five years into the future or twenty years into the past and back are more of what Hiro can handle with more precision and control.

I don't think so, because he loses about as much time as he gains...