Old pages

[Dirty]

I have a site where I have 5,000 new products each year, I never waned to deleted the old pages due to links pointing to them and keywords.  But I now have 20,000 plus pages, does having that many pages spread out my link juice or does it effect me in any other ways over having a site with 5,000 pages or should I keep not deleting old pages so I dont loose any links?

Along with that I currently do not link to my old pages from my site so Im guessing google does not get to them very often if at all, if you agree to still keep them should I link to them somewhere?

Because the products are not that simiiar and they do bring added value I dont think canonical would work here

[FishAcct]

You should maintain the pages if they receive traffic and you still stock the product, otherwise you may as well 301 redirect them to a) their parent product category b) an updated / similar product, folding the link juice of irrelevant pages back in to the site where it is more useful.