opening will rest (or should rest) on several
considerations: your style and temperament as
chessplayer, your time and aptitude for study,
ambitions as a player. The standard recommendation
Black counters in the centre, provoking an immediate crisis. White must defend or dodge.
The Caro Kann has a reputation of being a boring defence. It is quite deserved, I believe. Black aims for a solid position where White's space and activity can be held in check and in the end neutralised by exchanges. It is a system free from weaknesses and has been popular among top Grandmasters for many years.
It is not, however, your best choice if you want to play for a win, unless your technique is very good.
You have to be able to make a decent start in a game of chess, or you risk being blown away by your opponent's better development. Knowing a few openings in a bit of detail is some insurance against traps and ideas that you haven't seen before.
So, here are some variations in common openings that you can -- and should -- learn. At each turn, try and learn not just what is the right move(s) but why that move is preferred.
Your style: are you a Steady Eddie or a Bonkers Billie?
Your memory: can you commit the key traps and variations to memory?
Your study time: can you find and absorb what you need to play this system well?
Your aims: are you trying to get a playable position? are you trying to
set your opponent problems, so they make a mistake? are you inviting
your opponent to waltz with you blindfold on the edge of a cliff? are
you trying to lure them into unfamiliar territory, or a trap?
How to decide if the Dutch Defence is good for you
Just taking the Dutch Defence as an example...
Do you think it suits you? (Do your friends think it suits you?)
Do the ideas you read about go into your memory?
Do the ideas you remember actually turn up in your games?
Do you get good results with it?
Do the results in your games have anything to do with the opening?
Can your opponents avoid the lines you like to play?