The air filter? Yes, no question.
Instead of the factory disposable filter I would strongly suggest a modern high tech reusable filter. They provide more efficient airflow that results in improved economy and increased engine output that you can feel immediately. The initial cost is greater but the filter will last for the CR-V’s lifetime (with occasional washing and re-oiling). It will eventually pay for itself in fuel saved.
It also filters the air more effectively. This means less funk enters your engine.
Here is the very model designed for your car http://www.knfilters.com/search/appsearch.aspx?type=auto&year=2015&make=HONDA&model=CR-V&engine=2.4L
Honda has made it simple to install yourself with no tools. The airbox (most likely) clips open and closed). When it’s time to service simply remove the filter, wash it in your sink, allow it to dry, re oil and pop it back in. (Using the kit made specifically for your filter) http://www.knfilters.com/clningacc.htm.
The fuel filters typically can go many thousands of miles without needing replacement. At 30K you do not need fuel filter replacement unless the system has been significantly contaminated.
Use a fuel system conditioner that cleans the fuel system, especially the fuel injectors. Make sure it’s a kind that dehydrates the fuel system. Water inevitably gets in and can freeze. Simply pour the product in a near empty tank then fill up. I do this about three times a year.