It seems the Boot-time Scan is more useful and better than the Through Scan. So I guess if it is necessary, I mean, if we have some more time, may be it is better to do a Boot-time Scan monthly than a Through Scan, right?
I don't think so. It's for emergencies, infected computers.
Scanning into Windows is ok for the regular maintenance of the computer (you can evenly use the computer while the scanning is running in background, you have a graphical interface, etc.).