How to synchronize files from the site with uploading changes?

Question

Data synchronization

Good afternoon!
Tell me how to solve this problem:
1) There is a site on which files and folders are posted
2) After they were all downloaded with the structure preserved, a local copy of files and folders appeared
On the site, changes occur periodically in files and folders (change, addition, deletion) .
How to track these changes?
Instant notifications are not required, but for example 1 time per week or 1 time per month.
As I understand it, there are 2 solutions:
1) Download all files and check locally for changes in the structure and files (by name and checksum)
2) Check files before downloading (only by name apparently) and download only those that have been added
But which algorithm is more correct and what tools can be used to solve this problem?

Answer 1

FileZilla. Directory Comparison .