I use a USB flash drive for backup. Can I have it plugged in all the time, or should I plug it in only when I want to back up and then disconnect it again?

Having it plugged in won't hurt anything but if it is a backup device I would only connect it as needed.

USB flash drive are one of the least dependable of any media you could use. I recommend optical media. If you have NERO or ROXIO burner software you may have a packet writing utility bundled with it. Nero one is called InCD and Roxio is called Drag to Disk. Both these programs work like you may e using the thumb drive. Leave the CDR or CDRW in the drive and simply drag a file over to the icon. That will automatically burn the file to the CD.

I would follow the above advice. If you are using the USB drive for backup only, then you would also be better off burning anything you wouldn't want to lose to CD or DVD. USB drives are handy, but would be best to have a permanent copy of anything important that you may need in the future. As with any hardware, there can be problems trying to access USB devices at times, and you wouldn't want to lose anything important after having made the effort to backup in the first place.

Thanks for your responses. My backup program which I use daily, scans predetermined folders and copies all new or revised files which have the A attribute set (new letters, photographs, updated diary and database files, etc.), and it would be very cumbersome and do this manually to burn them on a CD. Maybe I should look into using an external hard drive; but then, I was under the impression that USB flash drives are more reliable because they don't have any moving parts.

There are two problems with flash media. There are a limited number of charge cycles and they also have a limit on the number of files. Can't detail more than that because I only use them to transport files occasionally as I think they were originally intended to be used.