If what I've said is true; what harm would it do if those people purged the cache at the end of their session? I think the advantages would far out way any disadvantages; whatever the reason for doing it. Not for me, but I guess it may for them. Really, the only reason I see to purge the cache is for privacy reasons.

As far as privacy versus security goes, I think it goes hand in hand. You brought up a good point with regards to history. Your right; you should delete it at the end of a session if you are worried about privacy, or security. At least that we agree on that. Privacy is a good reason to clear all cache/history-like data. When I started this, I was thinking only in terms of someone rummaging the cache on your machine.  Discovering the cached web bugs leads _me_ to consider cache flushing or looking for a tool to prevent/get rid of them.   Another reason to clear caches would be backups.  Backing up caches and other temporary files is truly a waste of time and space.   Rich

and increased speed/performance, as reasons for deleting cache at the end of a session. They must be saying these things for a reason. They all can't be wrong. I don't understand how cache can make anything _slower_. That would totally miss the point of cache. I'd go as far as saying that's a bug. There is a point when the number of files in a cache can grow to the point where the processing time to figure out if a page or image is IN the cache takes longer than the time to go get it. It is dependent on the speed of the CPU, disk drive, the amount of ram, the speed of the connection, the speed of the server delivering the page, etc... Thus it's very hard to quantify. Back in the late 90s a large cache would really slow down a typical computer. These days not so much or almost none unless you start getting 10,000s of files in the cache.

There is a point when the number of files in a cache can grow to the point where the processing time to figure out if a page or image is IN the cache takes longer than the time to go get it. Finding out whether something is cached is an O(1) operation afaik.

It is dependent on the speed of the CPU, disk drive, the amount of ram, the speed of the connection, the speed of the server delivering the page, etc... Thus it's very hard to quantify. Back in the late 90s a large cache would really slow down a typical computer. These days not so much or almost none unless you start getting 10,000s of files in the cache. I have been on peoples computers running IE, where I've deleted their temporary Internet files, because pages were loading very slowly. Some have taken a couple of minutes to complete the process. After it finished, the pages loaded quicker. These were all pentium _base_d, with at least 256 of ram, and plenty of room left on the hard drive. When I asked if they ever deleted it previously, most didn't even know what cache was.

and increased speed/performance, as reasons for deleting cache at the end of a session. They must be saying these things for a reason. They all can't be wrong. I don't understand how cache can make anything _slower_. That would totally miss the point of cache. I'd go as far as saying that's a bug. Try entering; large browser cache file slows down computer , in a google search. As an example, the following is an excerpt taken from this Microsoft article. http://www.microsoft.com/windows/ie/community/columns/performance.mspx Some of the fixes you will see below are not specific to Internet Explorer. Experience has taught me that it is always a good idea to take a holistic approach when working on browser slow downs. Adjust Internet Explorer’s cache size One of the side effects of today’s mega-large hard drives is that Internet Explorer may automatically set its cache limit to a ridiculously large size, or the computer’s user will choose an extremely large cache size because they have the room. I have seen computers with a gigabyte (G or more of space dedicated to cached Web pages. This is far too much. Any time saved by caching so many pages is wiped out by the time it takes Internet Explorer to index and then later find and load those pages. Also, the risk of cache corruption increases exponentially as the size of the cache increases. I generally recommend a cache size of 50 to 100 megabytes (M for the average user, with 100 MB being for those with broadband and a newer (faster) PC. If you are in the habit of downloading very large files then you should consider increasing the size of your cache so that it will comfortably fit the size of your largest download plus about 50 MB.