
Continuity mistake: When David and Saavik approach Spock's tube on Genesis, you can see quite a bit of dirt covering the words' red lettering, but when it does another shot of the lettering, it is noticeably cleaner. (00:30:25)

Continuity mistake: In the scene early in the movie where Kirk is talking to Sarek the guns on the wall are suddenly rearranged. (00:23:50 - 00:24:45)

Revealing mistake: When the Enterprise explodes, some of the debris briefly turns transparent. (01:12:15)
Chosen answer: The Enterprise may have been extensively refurbished, but that does not mean it is entirely new. The ship is still 20 years old. Also, that was Decker's comment, and it may have been an over-exaggeration. Newer ships were being designed and built in the meantime, so even if the Enterprise was still mechanically sound, the technology may have advanced so much that it was not possible or it wasn't economically feasible to continually retrofit older vessels.
raywest ★