There are many things we might put in the filters to change how they work but that often is better left until we get some idea of how it works to start and a bit of experience to know what we do is right. The filters are often designed and made pretty well but after some time we may be able to see ways to save some money by using cheap cut-to fit pads or other items, rather than the ready made sorts which can be very expensive to change often.
And that thought gets over into knowing more about filters as they can be very simple, once we take close look and understand what they do. Once we look at what the filter does, we can decide if we need more of one particular aspect of those functions and change the media to suit our particular needs better.
Mechanical filtering? That's just the way a filter "strains" the debris from the water and keep the tank looking in clean, even though the debris is only hidden, not truly out of the tank until we clean the filter. So we want something quick, easy and cheap to change or clean.
Bio filtering is giving the good bacteria spaces to live and most any surface that has lots of tiny spaces that get good water flow will do for the bacteria. So we don't really need it to be a well made off the shelf and expensive item but perhaps a couple sponges. After some time, there will be bacteria living on everything in the tank and the portion in the filter is less critical.
Chemical filtering like carbon? Most find we don't need the constant mess and work of it as the tank works fine without carbon-- unless we have color or smells which most will not have, so we lay the carbon back for something we might need someday.
So that leaves me to recommend using a filter for a while to get to know what each item does and then you may want more of one or another. A bunch of active fish that tend to make a mess may mean more mechanical even if that means less bio. but we often find we want to keep more fish and choose more bio and less mechanical. Or we may find the design is good but we want to stop paying the high price to buy a cartridge and start getting something cheap to cut down.
A bit of time is often needed as each tank does work slightly different just as we each have differing needs and desires for the tank.