I've seen an uptick in website traffic from China and Russia, plus a few other countries on the naughty list. As I see the IP addresses, I'm blocking them at the router level, which will help significantly with website speed.
We delete "Guest" accounts nearly every day. A guest account is considered any visitor to the website that does not create an account. Sometimes these guests create a shopping cart, but they nearly always abandon it. These abandoned shopping carts are deleted as well.
We also delete shopping carts that have not been converted into a purchase after 30 days. The reason is that after 30 days if the cart hasn't been converted into a sale, it never will. If you want to keep track of something, add it to your Wishlist instead. Those are only cleaned out once a year or so.