forgive my very naive question here, but -
1. i never backup
2. wallet is a windows pc, not connected to the net.
3. i close the wallet, then winrar the wallet.dat file with strong p/w
4. then delete wallet.dat and close pc for a long time.
if i need to open the wallet, i open the rar, and then the wallet.
to-date, no problems with any coins i've had.
am i not assessing a risk properly here?
i can't rationally explain why, but i don't have trust in built-in backup options [all s/w].
Here is your problem. Eventually hard drives die. Sooner or later, the drive in your windows box will stop working. At that point, you should still know how to get your coins.
I suggest copying your .rar to a USB stick, or another drive, or a CD, or some kind of media that you can read in another computer. And then keep that stick, or CD, or whatever it is, safe.
The encrypted .rar is not really protection: .rar archives use a light encryption format that's fairly easy to brute force (40-bit keys IIRC). But it's a good scramble (prevents the file name etc from being visible anyway, or malware file-format analyzers from recognizing a renamed wallet.dat file) for a wallet that's kept in encrypted form to start with - and yours *is* kept encrypted by the client, right? With a strong password, right?