If you're new to lens filtration, these questions undoubtedly have been on your mind. Luckily, this infographic acts as a perfect cheat sheet to show you the effects of different filters, as well the conditions in which you should utilize them. Check it out below:
Now that we're entrenched in the digital age, filtration can be achieved, in many cases, in post, so some filmmakers find certain filters, like B&W and cooling/warming filters somewhat obsolete. (Especially if you're not shooting on film.) However, that "fix it in post" mantra will eventually get you in trouble -- like when you can't fix it in post and could've saved yourself a huge headache by being prepared. If anything, bringing along a polarizer and some neutral density filters is a good habit to get into.
Of course, you could always read about lens filters, how to use them, what they do, how much they cost, etc. (But we're visual animals in the film industry, so this infographic is particularly gratifying to peruse.)