I haven’t use fryers for over 20 years but I remember them well.
When you say regularly do you mean every day? It is batter and such that dislodge from the food you are frying that need to be filtered everyday as they continue to cook and burn and will shorten the life of your oil.
If the oil turns dark and your food tastes burnt even when it isn’t, that is a good indication. Don’t forget to clean your heating elements periodically.
They make oil extenders that help lengthen the shelf life of your oil. I have had good success with them in the past.
