I’ve gone back and forth on this over the years, and for easy maintenance specifically, it really depends on what kind of “easy” you’re aiming for.
Cartridge filters are easier in a hands-on sense. When they’re clean, you just pull them out and hose them off. No valves, no discharge line, no watching pressure gauges closely. If you don’t mind getting a little wet and doing a rinse every so often, it’s pretty straightforward. They’re also nice if you’re in an area where water use matters, since there’s no backwashing.
Sand filters feel easier in a more “set it and forget it” way. You can ignore them longer, especially during busy swim weeks. When pressure rises, you flip a lever, let it backwash, and you’re done. No lifting, no scrubbing. The tradeoff is water usage and the occasional bigger job when the sand eventually needs attention.
One thing people don’t always mention is space and access. If your equipment pad is tight or awkward to work around, cartridges can be annoying to remove and clean. In those setups, sand can actually be less hassle overall.
If your goal is the least thinking and least physical effort over time, sand usually wins. If your goal is cleaner filtration with fewer moving parts and you don’t mind periodic rinsing, cartridge makes sense. Neither is wrong, it’s more about which type of “maintenance” fits your tolerance better.