I would say that my personal website is at least currently a "small" website.
It is a MediaWiki-based all-core website without images at all and of about 750 webpages of generally no more than 5,000 bytes each. By current principle it shouldn't pass the 1,000 webpages count.
If I had the right circumstance I would have run my website cacheless but I need caching for MediaWiki rate limiting.
I think that often times caching mechanisms can consume too many resources in comparison to a website (such as of myself?) and therefore cause more performance trouble than benefit in the long run.
My current hosting provider offers me Memcached which MediaWiki can utilize for Rate limiting but another hosting company offers me to choose between Memcached and APCu (which is also utilizable by MediaWiki for that cause). I don't know how to determine which should be lighter in generally every aspect, at least in my use case.
How to determine if APCu is overall lighter than Memcached in a use case?
By lighter I mean "will consume significantly less computing resources", let along won't have any chance to badly effect my MediaWiki website