Well, I'm not sure I'd say "never" to an upgrade.
It's not something I've done (yet) but if I were resurrecting an old model (that prompted for upgrade) with the intention of spending some time enchancing it, I would probably elect to go for the upgrade purely to stop all the upgrade prompts every time I went to work on it. But I would save it under a new name and do a "diff" to see what changed, then manually visually inspect the changed parts for correctness
It's not something I've done (yet) but if I were resurrecting an old model (that prompted for upgrade) with the intention of spending some time enchancing it, I would probably elect to go for the upgrade purely to stop all the upgrade prompts every time I went to work on it. But I would save it under a new name and do a "diff" to see what changed, then manually visually inspect the changed parts for correctness