How long should I keep the old backups on my computer?
Keeping old backups on your computer may in special cases be important for your website. That's why because more and more the operation of websites is suspended due to security holes in their software (not updated software, wrong permissions on files and folders, etc.) that allow internet users to carry out malicious actions, without these to be easily noticed by the owners of the websites. Also a violation can be used in the future, for example, a unwanted file can be uploaded to the server and used perhaps months later, for a malicious action/attack in other websites. In such cases a recent backup may contain these unwanted files so its recovery will not solve the problem, while an older backup may be clean.
IP.GR checks the files that are uploaded to their servers with firewall applications against viruses and all known types of malicious actions and informs customers when an adverse event occurs. However, there are cases that clean files are used in a bad way. For example, if some vulnerability of your website allow a user to upload a seemingly innocent file for sending emails it is obvious that it will not be characterized as malicious action if the file that's uploaded is not a well-known virus. But there is a serious possibility that this file might not be innocent as it may be used for sending spam emails. Therefore the use of this file is malicious and not the existence of it. In such a case if you have an older backup at your disposal can help significantly to the website restoration to a previous clean state or even in the identification of the malicious file.