> How much of a session is based on "reading players" vs "playing the odds"?

Several good answers here, but I will add my own take.

“Playing the odds” is basically playing good, fundamental poker. This is a baseline that most players will use when sitting down at a table of unknown players. This is often called a “balanced” strategy (note some people erroneously call this “GTO strategy, assuming the balance, which is not actually what GTO is).

“Reading players” is a thing, but it can be broken up into (at least) two categories: 1) physical tells, and 2) player habits.

Physical tells is not a big thing. Some people give off a lot of tells, but some folks are also decent (not good) at giving reverse tells. Honestly, you can be a wildly successful poker player while knowing nothing about physical tells.

(Side note: One of the most reliable tells is bet timing tells. This can sometimes even be a tell online, especially when people are taking shots at higher stakes or are deep in a tournament. It can also be faked, but some folks are super reliable with timing tells, and they don’t realize it.)

The second kind of tell is player tendencies — things like when players play too many hands or when they play too few (e.g., fold too often).

One very reliable way for good players to smooth out their earnings curve is figure out which players fold too often and in which spots. Once they’ve figured that out, they try to set up that spot and basically print low-risk (sometimes even no-risk) chips.

Taking advantage of these tendencies is called an “exploitative” strategy (as opposed to the “balanced” strategy mentioned above).

Really good players can take rec players on a journey through a series of emotions (and accompanying predictable gameplay) such that the good player can read the rec player like a book. The odds tip heavily in favor of the good player at this point.

Pro player and strong amateur players are so far ahead of recs in ways that the recs don’t even realize.