Question regarding case fans

[Akonji]

Some time ago I created a thread to get some help with a new build.
Following the advice, I ended up with a satisfying build, but now I have another question to which I could not find an answer.
The case I've ordered is the Fractal Design Define R5 (https://www.alternate.co.uk/Fractal-...7?event=search) which comes standard with two 140 mm fans (one in the front and the other in the back).

Now I'm wondering whether or not I should add a third fan, and if so, where I should place it.
From what I've found, the Noctua NF-A14 FLX (https://www.alternate.co.uk/Noctua/N...7?tk=7&lk=9346) seems to be a good fan to get and it should be placed in the front too according to some PC sites.

I'm hoping someone can help me with this question.
If more information is required that is missing, please say so and I'll add it.

[Akonji]

Thank you for answering my question.
The stock fans in this case seem to be decent enough that those don't need replacing, but I'll order an extra fan now that you've given a good explanation as to why it'd be better.