Under the Advanced Tab, there is a box to check or uncheck (the default is a checked box) "Only delete files in Windows Temp folders older than 48 hours". If I uncheck the box, then I assume CCleaner will delete all the files in the Windows Temp folder. Won't that result in a more thorough cleaning? Is there any disadvantage in unchecking the box, so that all Windows Temp files are deleted?
Yes, if you uncheck that box, CCleaner will not retain any temp files (that are not protected). It's just a personal preference; some people like to keep their garbage a few days before they throw it out
As the old saying goes Fish and Visitors Smell After 3 Days so maybe they should change it to 72 hourssome people like to keep their garbage a few days before they throw it out