Two questions ;-)

[Dylan_Bain]

Question 1 - How long should a adventure-esque visual novel be? I was aiming for round about 5 hours, is this about right?

Question 2 - How do you measure how long the visual novel is without reading it, you know, a quicker way?

[firecat]

1. as long as you want and 5 hours would seem kind of long almost like a whole book like harry potter.

2. there is no right answer for this question, people read faster or slower. making a novel game to end exactly on time with the reader is impossible.

[Hijiri]

Question 1 - How long should a adventure-esque visual novel be? I was aiming for round about 5 hours, is this about right?

Question 2 - How do you measure how long the visual novel is without reading it, you know, a quicker way?

1- Well the average adult will read around 15k-18k words an hour, so if you want to make a 5hr game, you'd have to write about 75k-90k words, which is about the length of a rather large novel. (Average novel length is about 64k words)

2- Word count, as I showed above. You can roughly estimate it with the average, but it all depends on reader speed.

[DrivenByTheWind]

You could look up the word count for the games that are WIP and/or completed. I do believe most post their word count. You can compare to get an idea of the word count/run time ratio.