The reasons to use HEM or PT @2nl, in order of my perceived importance:
1. You want to improve your game by analyzing and tracking your own play
2. You multitable 4+ tables and need help keeping tabs on everyone
3. You want to maximize your edge, plan on moving up stakes in the future, and would like practice with the HUD and software
Reasons why
buying tracking software @ 2nl might not make sense:
1. Your 2nl
bankroll is less than the cost of the software.
2. You only play one or two tables simultaneously, take good notes, and can follow and be profitable at the game this way.
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My personal story is that I started out without any poker software. I made a $0 bankroll challenge for myself and get started with starting capital promos and
freerolls. Once my bankroll got up to about $120 or so and I was considering moving up stakes to 5nl, I decided to use the Poker Tracker 60-day trial to see how it was, and if I liked it and was profitable with it I would probably be able to afford the micro version of the software after 60 days.
I was profitable after 60 days, and the micro version was then easily purchasable at that time without making too much a dent in my bankroll and keeping me well rolled for the stakes I was at.
When I still had my roll at FTP, I was playing 6-8 tables of 6-max cash ring 25nl. With that number of tables and stakes, I wouldn't think of starting a session without my tracker running. Less tables or stakes and it can still be profitable without a tracker, although not maximally so.