People say a lot of things: possibly, some of what they say is true, and some of what they say is untrue.
According to Qur'an and hadith, jinn and sihr can cause harm. However, many other things are also dangerous; for instance, animals are dangerous, and driving is dangerous. So it is good not to focus too much on being afraid of these things, since fear can be its own enemy.
Also, it is better not to cast too many aspersions on the other half of the thaqalayn, since most jinn are not going around trying to possess or harm people; in fact, it is related from Imam al-Baqir (A) that some of the jinn are better followers of the Imams than humans.
Some things that offer protection are reciting or listening to Qur'an, keeping ayat of the Qur'an or the names of Allah displayed on the wall, reciting du'as, praying salat regularly, avoiding certain types of sins or places where these sins are committed (such as sins involving violence, unhealthy sexuality, or drugs/alcohol), and living a healthy and balanced lifestyle. (A person who is living a healthy and balanced lifestyle is generally better able to cope with the challenges of life, whatever they are, although of course sometimes we do not have a choice about how we are living).
I am also favourable to the narration that says that keeping small animals wards off the harm of shayatin, although I understand that keeping domestic animals is a personal preference!
Also, if someone genuinely considers it a priority to keep jinn and sihr out of their life, it is good to avoid seeking out people or places associated with these things (for instance, do not take up paranormal investigation). This may not be relevant to you personally but may be relevant to others.
Allah protects.
