Is it neccessary to clear browser cache periodically?
Caches, if behaving properly [which they do almost always], are like soap…
…self-cleaning.
The only time you need to clear any cache is if you have clear indication it is in some way misbehaving; otherwise you can just let it do its job.
It will naturally clear old data to make way for new & ought to maintain a relatively stable size over time.
Typically every browser has a maximum cache size that can be configured.
Internet Explorer typically set it to some percentage of the disk space available, either 5% or 10%, other browser may use a percentage or a fixed cache size. Firefox defaults, I believe, to a 1GB cache and I think Chrome is a similar amount.
Upon reaching the limit the programs will purge items from the cache on a least recently used basis.
No browser cache should simply grow to occupy an entire disk. It would be surprising for any items as old as 5 years to still be in the cache and you probably don't need to worry.
Firefox: changing the cache size
Chrome: disk cache size registry settings
If in doubt, search for <browser> cache size in your favourite search engine.
There is no way that a modern browser will allow your drive to fill up with cached files.
Each browser is set to a limit that won't be passed. You can manually change those limits if you so wish:
Firefox
Firefox (latest version) is set to a maximum limit of 1024 MB (at least that's the value for me and I have never changed it) and you can change that by accessing "about:config" in your URL address bar, and modify the value of browser.cache.disk.capacity.
Chrome
Chrome's settings appears to be a little trickier and the default value is a percentage out of your drive free space. You can find how to change that value here What is Chrome default cache size limit?
Edge
Edge is sharing the same settings as the old internet explorer and the default seems to be automatic as well. Go to Control Panel - Internet Options and under the General tab you will find a Settings button for "Browsing history".