I see no reason why Civvie ships shouldn't track a maintenance clock, with the ability to reroll for a new ship. I think "just" 10 years (an arbitrary, illustrative value I know) isn't quite right-- you might have a design that you use for well over 10 years, like my 25-cargo hold superfreighter that flies at about 4k km/s. No need to replace an old freighter with the same design. But all those single-hold craft running around; not much need for them to do much of anything anymore. I've just decided to ignore it, and once I have 10 or 15 freighters running on a line, I upgrade them with newer vessels. But I don't do conventional starts, which would likely result in dozens of nauseatingly slow freighers flitting about.