GNU Wget documents -c, or --continue, for resuming a download left by an earlier invocation. It treats the existing local file as the first part of the remote file and requests the remainder. This is a useful assumption for an unchanged object, not proof that two files belong together.

The manual warns that when the remote file has changed and is now larger, Wget can append data to the old local content and produce a garbled result. A matching name or a plausible final size does not establish integrity. An interrupted download is therefore not automatically a safe candidate for continuation.

If the server does not support continuation, the manual says Wget restarts the download and overwrites the local file. Preserve any partial file you need before retrying. For software or system images, prefer a stable version-specific URL and verify the completed file against authenticated publisher checksums or signatures.

Verdict: use continuation only when you have reason to trust the remote object’s identity and can validate the result. Otherwise download a fresh copy to a separate destination. This is a documentation review, not a reliability test; no bandwidth saving, throughput result or universal guarantee has been measured by YNIX.