Not sure how anybody would know what gear they’ll need to take if they don’t have any idea about the size and configuration of the venue. Do you just take everything you own and hope you have what you need?
I already know what I will need once I have given them a quote.
If they have 25 - 100 guests I am going to set up 2 speakers. I will bring 2 extra, and leave in the car.
If they have 100 to 180 guests BUT the venue has some serious stairs involved in the load in then I bring the same anyway.
If the venue has no stairs, and 100 to 180 guests, then I bring a sub, 2 speakers, and 2 extra speakers left in car.
If the event has over 180 guests I generally plan to bring 2 subs with me + the 2 speakers + 2 speakers left in the car.
If they have over 400 guests, I know I will be setting up 2 subs, and 4 speakers.
My light show has generally been the same SIZE at every event these days so that does not really change even though I change out some lights from time to time.
All other sound euipment is brought to all events.
Honestly, The only reason I may want to visit a unknown venue is to figure out where to set up the Up Lights IF the client has a UP Light package added to their event. However, this is not needed either. Arriving early, and spending an additional 5 to 10 minutes figuring up light placement out is really all it takes.