How long is a ship used?

[Lt.Juliet]

So Star Fleet would use every vessel as long as it could be upgraded?

 

[Saturn0660]

So Star Fleet would use every vessel as long as it could be upgraded?

I would think so. I would think it would be far cheaper to upgrade then to replace.

 

[Lt.Juliet]

Is there a known graveyard for old vessels?
In one VOY episode we can see something like this in the delta quadrant, but does Star Fleet have something like that?

 

[F. King Daniel]

Yep, Qualor II seen in "Unification" part 2. Many of the Wolf 359 ships ended up there, along with the Planet of the Titans Enterprise.

 

[Saturn0660]

Is there a known graveyard for old vessels?
In one VOY episode we can see something like this in the delta quadrant, but does Star Fleet have something like that?

Sure, there was a TNG where the Enterprise went looking for a ship in a "graveyard" I think it was part of Unification