I saw a couple You tube videos about the High pressure fuel system in the Fit that causes issues with fuel getting in the oil. Is there any truth to this and which model years does it affect ?

 

That's true to some extent for any car with direct fuel injection. For Fits, that's 2015+.

It's not as bad if well maintained and driven frequently, but low mileage cars will get hit worse by this since they sit around a lot more and usually don't get up to temperature as often, which causes it to evaporate out of the oil.

 

Being retired I don't drive every day, so would the Fit be a bad "fit" so to speak ?

 

It's a combination of how often and how far you drive. If you only drive once or twice per week but go for 30+ miles down the highway you'll be fine. If you drive every day of the week but only a couple miles per trip you will rarely get your engine warmed up fully and that's hard on things. Note that this isn't a Fit issue so much as an internal combustion engine issue.

I ride my bike or use our Nissan Leaf EV for short/local trips and I work from home, so my Fit often goes weeks (or months) without being driven. When I do drive the Fit it's almost always 100+ miles roundtrip. I'm not about it.

 

Well being a long time car nut, gas in the oil is never a good thing. Matter of fact its one of those things you usually check for in a used car, but that was a long time before most cars even had fuel injection, whether thru a throttle body or direct.
One way to help is to change the oil much more often. Not sure what the intervals are for a Honda Fit, or even the oil type used, but its probably around 5000 - 10000. So you could always go with changing it to around every 3000 miles.
Or just get one before 2015.