For most overall healthy people taking antihistamines is safe to do.
But for some people taking antihistamines everyday may cause other health issues.
When it comes to medicine the antihistamines can usually be taken safely everyday without much issue but you should consult your doctor just to be safe.
Most people only need to take antihistamines when they have allergies that are flaring up such as during spring allergies, winter allergies etc.
When your allergy symptoms go away it's usually a good idea to stop taking the antihistamines and then only take the antihistamines again when the allergies flare up again.
This is what I do as I hate taking medicines including antihistamines unless I really need too.
So I take the antihistamines when my allergies are flaring up and then stop taking the antihistamines until the allergies flare up again.