I never kept a log of how many trips I've done to Longcliffe during the lifespan of the project, but it would be well over a hundred, with at least half underground - I was generally one of the haulers when we were still emptying the shaft. But I like the familiarity of repeat visits as you get to know a place really well and inevitably start to find more detail and understand the structure better (and maybe find more leads) as a result.
Paradoxically there are many places I probably shouldn't go to again, simply as there's not much to be gained for the effort - other than another dose of radon, which is very high in the northern catchment where I am, and is increasingly something I'm bearing in mind, apart from coronavirus!