What have you learned? Check out the following 3 questions, multiple choice possible.
What indicates it is time to change the oil filter?
The oil pressure light comes on.
The engine makes weird noises.
There is no good indicator as you cannot look inside the filter.
You should not buy comparable cheap air filters because:
Cheap air filters can damage the air mass flow meter sensor.
Cheaper materials can cause leaking due to brittleness and poor fit.
The absence of flame-retardant is dangerous: The ember of a cigarette in contact with the filter medium could cause a fire.
Modern engines become increasingly powerful. Consequently the requirements for air filters become:
Lower and lower as modern engines are by default better protected against dirt.
Higher and higher as filters have to protect the highly precise engines.
Check my answers