Sand Filters vs Cartridge Filters
They vary widely in cost and ease of use. Getting the right sized and type of filter for your pool can make all the difference in how easy it is to maintain and clean your pool.

Sand filters use a specially graded sand as the filter media. The water enters the tank through the diffuser.  As the water goes down through the bed of sand, the dirt and debris is trapped between the grains of sand.  When the water reaches the bottom of the filter, it enters the laterals and is returned to the pool.
Sand filters filter out debris down to about 40 microns in size.  Anything smaller than 40 microns will probably not be filtered out. Filter sand should be replaced every 3-5 years

Cartridge filters use a paper-type cartridge as the filter media.  They do not filter as finely as DE, and in our experience produce about the same water quality as sand filtration.
Cartridge filters used to have a bad reputation as a nuisance to maintain, but manufacturers have come up with newer filters with enough surface area (300-500 square feet) to need cleaning only once or twice each year.  This makes the maintenance issue a plus with these filters.