I have immense respect for guys who do this kind of work. My only pit experience was filling in for someone one night at an amateur production of "Funny Girl", which seemed like a pretty straight forward score(until I realised everything was in cut time at fast tempos). I survived it by being prepared, attending all the orchestra rehearsals and observing the bassist who I was filling in for but still nothing could prepare a novice like me for that headspace and for having to watch a conductor while stressing about keeping up with the score in front of me. I was sharing the pit with people who play for our local philharmoic. It's second nature to them and I can only admire how those guys do it.