At least with novels there's no on-screen comparison. And re-using or re-introducing general ideas, aliens, conflicts, relationships, all of that is fine. But re-using or re-purposing specific
lines or scenes from previous on-screen Trek is risky. To me it's okay when it's done in a moment (a brief
moment) that's meant to be fun and not at a crucial time in the film or series. Quark quoting Picard's "this far, no farther" line comes to mind. That was meant to be a parody. As Ron Moore said about that line: "I take great glee at mocking my own work." On the other hand -- if it's overdone or placed in the show or film at the wrong time (a serious or crucial scene or scenes), quoting previous on-srceen Trek can become a parody for some viewers even if
that is not the intent. And because of that, it can potentially ruin a show or film for some people. That's the risk.