So round here in the south some of the best fried chicken you will ever eat comes from used fried chicken oil. Decide for yourself if you're down with that or not, but these southern woods folks can cook and the chicken is good. I don't cook that way... but I definitely have enjoyed their cooking that way.
I think it is ok if you have a modern sealing deep fryer that has a light to notify you when items should be cooked. The temperatures of them kill the bacteria as the oil gets quite hot. Then since it seals tightly it can be stored at room temperature. Since the oil was quite hot and then needed to cool down. Most of them take enough time even with cool wall deep fryers that it should be safe. However if there is some debris you may want to strain it off though a cheese cloth, clean the fryer and then reuse. I wouldn't keep oil for more than 2-3 months max. Everything should be thoroughly cleaned by then.
Old deep friers didn't always reach the heats they do now. They also took longer to cook. If you hygienically handle chicken or meat before cooking usually it is safe. One thing I do sometimes is poor boiling water over all surfaces of raw chicken. This kills surface bacteria and also tightens the skin and seems to produce juicier chicken.(when baked in an oven) Some items cooked in oil need the oil to be dumped out and not reused. But I unfortunately can't remember which items were on that list but I think one type of fish was. Things like veggie tempura or french fries the oil can be reused lots of times. Though tempura batter can leave little messy bits in the frier.
Your country should have a food standards website that you can Google for. Go there and they will have food handling tips and helpful information on other things. I took food handling long ago in more than one country due to slight differences in their standards.