Cabin filter is a 4 minutes job. 6 bolts to remove. Its not critical, but some say that when the filter is full, it is hard on the blower motor and can cause it to fail (a major pain to replace).
Check belts etc, but if they don't look bad or make suspicious noises, just keep them.
If the coolant pump has been changed, coolant has been flushed at the same time. Usually coolant can stay for 3/4 yr. You can test it with an acidity strip.