I think it's a great idea not only before sitting down and playing but even instead of it. If you go for several weeks and simply observe the game you get a lot of information about the usual atmosphere, who's a regular at those stakes, who likes to drink and how their play changes the more they drink, even discover poker tells. And the best thing: it's free, you are not risking any money to get all that valuable information.
At the very least you should wait to start until the BB. I like to watch a table before to see if there are people I know and whether I have notes on anyone. With 2-3 orbits you can also see how often pots are 3-bet pre, who is aggressive/ passive, are there lots of limpers and or multiway pots. All very valuable info.
The only caveat is that you can't judge someone's tendencies for sure that quickly so use the info you have learned but don't be married to it.
I prefer to play sits and go, because they are fast, and do not spend too long in tournaments.
I think not worth playing tournaments where you spend many hours because if you do not get to the final table, you only earn a few dollars, maybe it's more profitable to play tournaments up $ 10.
It is far better to sit at the table and observe it.
I mean, it s a cash game, you are in no rush at all. Usually you buy in for ~200bbs.
At least it's a better view of players, how they behave, you can closely see when someone shows a card, a hand.
At the same time, observing the table for half an hour then sitting, I would feel discomfort - being new to the table, only just getting the first hand etc.
If I was at the table for half an hour and folded every hand, I feel comfortable, already picked up on the dynamics of the game, on the pace, probably figured a couple of players along the way.
It is a good practice to take a few minutes and observe first before entering a cash table ... I do it every time I have time ... that gives you an idea of what the players' rhythm is ... if they are very aggressive ... or very passive ... etc ...!
I am not playing cash but there are many people I know that it takes a certain time to look at the table before entering, so he sees what types of players are marking them and get the most out of his notes.
You could definitely sit and have a look at how he table is playing for a little bit before you sit down and play, not the worst idea at all. I would honestly rather sit down at a table live or online and just play extremely tight for about the first hour. This should show you how players are playing the game and you can still be at the table and play a hand or two in the first hour your there. That is what I like to do, its slightly harder to just find out a table dynamic and how they're playing by watching than just sitting down to play, you get a better feel of whats going on just play very tight. I hope this helps you out, just get in there and play but very tight for about the first hour. The first hour should tell you how things are going at that table and you get to actually play some monsters if you happen pick them up.
The ability to choose tables is very important. But the search for a good table these days is only half the battle, it is also important to find a place to the left of the fish. It is in such positions that a lot of money is made in this game.
I do not play poker on cash tables. I only know the basics of playing cash tables. And almost everything that is offered to you here is the norm. I believe that for any game you need to look at the game of your future opponents, this will not hurt you.