On the plus side, in the modern era, you can easily find a walkthrough to help you through whatever. Though many are not well-structured to avoid spoilers when you drop into the middle of them.

I don't do a ton of adventure gaming, but I have gone through most of the episodic Sam & Max games. I estimate about 1 walkthrough consult per 2 games overall, and about a 50/50 split between "oh crap I should have gotten that myself" and "oh, I was never going to get that" results (with the occasional "oh I was right and I just didn't click on the right thing or notice the tiny little widget" that really makes me glad I just looked).

Day of the Tentacle was probably the largest game I've done with 0 consults, though I was probably stuck enough to justify it a couple of times. One of the heights of the genre, there.