What is the best way to deal with media cache setup across PR/AE/M-encoder,Au,...?

Hi,

I understand there is some hidden communication between these programs that seem to override preferences set from within a program. This may help let the programs find these files, but makes it difficult to identify and delete cache files that use up quite a bit of space over time. So to understand a little better:

1. Are ALL of these files just temporary needed for better playback? In other words:

a. even if you delete them they will just have to recreate themselves when you open a older project that can't find them - as long as you have all your regular sources available and connected? Worst case: it will take a while until a older project will recreate the missing cache files. Just time, no headaches.

or

b. are there instances where YOU have to manually recreate, reconnect a file that just has a cryptic name you would not know where and how to do? Files I am not sure about are audiophiles that were created/treated in Encore... also some media files seem to have "partner" files ( usually same name, different ending ) that accompany them and may or may not be needed. If this is the case: how do you identify ( consolidate ) these files before deleting the cache files?

2. As AE, PR and media encoder ( and ? ) with each new upgrade ( they go by year now?) seem to be set to work with each - PR 2017 opened AE 2017 and not AE 2015... - would it best to install them all at the same time and set ALL their cache preferences to ONE location: A folder simply labeled "year-Cache" ( on a dedicated Cache SSD if possible ) Do you still have to do this from within each program or can it be done across all programs that speak to each other?

Thanks