As well as you don't generate any new receiving address, then the backup is OK.
In another word, prepare enough receiving addresses for future usage, then start to backup.
This is very bad advice and is likely to result in people losing bitcoins if they think you know what you are talking about.
Please don't give advice to others if you are just guessing and don't understand how the wallet works. Some newbie that doesn't realize that you're just making stuff up is likely to lose money after following your advice.