On this site, in the top of the page there is an option for a red markers, next to the word review, which should show how many posts are waiting for your review.
On TSE, when under 10K rep, the warner showed how many post were waiting in the suggested edits queue and that worked well. Only tag edits I had waiting for others gave a false message.
When reaching 10K, the marker shows up for all posts in all the review queues, and it does not reset/disappear when I do reviews. Often it shows a wrong number for hours.
When working well it is a useful feature that reminds you to check the review queues, but when stuck it is useless.