How much is winrate affected by how long a session you can play?

[Talking Poker]

Well, looking just at the math:

If I were to immediately allow you to but in for 200 BBs at the same tables that everyone else is only allowed to buy in for 100 BBs, how would that affect your win rate? Assuming you are a winning player, I think it obviously would move it up.

And that's basically what you are doing by extending your session length. The longer you play, the more money you will have sitting on the table in front of you (even if you are down for the session, as long as you keep reloading), so the higher your win rate should be.

The problem with this logic is that there are other factors that need to be considered. To name a few:

1. Getting tired.
2. Playing worse (for whatever reason) when you have 2x, 3x, 4x the max buy in sitting in front of you.
3. Table/Seat Selection - The table you are at now is certainly not the same as the one you chose 4 hours ago.

That's all I can come up with off the top of my head, but I'm sure there are more factors too.

So, does the increase in win rate because of the larger stack make up for the negative factors that arise from playing long sessions? Speaking generally for the average playuer, I'll guess no. But I really think this is an individual thing. #3 is out of our control, but some people will be more affected by #1 and #2 than others.