A sediment filter does its job out of sight, and most owners only notice it when the shower slows down or the water looks cloudy. A few checks done on a set schedule catch the problem early and keep the rest of the system protected.
Read the pressure before and after the filter
If your system has gauges on both sides of the filter, the difference between the two readings is the pressure drop. A growing drop means the filter is catching more material and is closing up. Write the readings down each time you check. The number that matters is the trend, not a single reading. When the drop climbs well past where it started, plan the change.
Check the housing and the seals
Look at the housing for cracks, weeping at the joints, and residue around the seal. Inspect the O-rings when you open the housing. A dry or flattened ring can leak or let water bypass the cartridge. Use only the lubricant the manufacturer names, in the amount they specify. Too much grease can attract grit and cause trouble later.
Look inside at each change
When you change the cartridge, look at what came out. Heavy fine sediment points to a source problem that the filter is working on. Very dark or slimy material may mean the filter is staying wet between changes and something is growing in it. Note what you see in the log, because a pattern over several changes tells you more than one change does.
Set the change trigger
Decide on the trigger before the filter gives trouble. Use the pressure drop from the gauges, the flow at the tap, or the manufacturer's stated interval, whichever comes first. Keep spare cartridges on hand so a change does not wait on a delivery.
Shut down and change safely
Follow the manufacturer's steps for isolating the housing, relieving pressure, and reassembling it. Do not run the system with the housing open or the bowl loose. After the change, run a tap to clear air and confirm the flow and gauge readings return to normal.
Keep a simple log
Use one page or one note on the equipment. For each check, record the gauge readings, any seal or housing condition, the cartridge changed, and who did the work. Keep the manual and the log together. When someone in the house takes over the routine, the log tells them what has been done and what is due next.