A Deep Well Liner ensures the diameter of your well to remain open and consistent. It also strengthens and prevents future sand penetration from well casing corrosion -or- splitting from the seams.
It has been some time now that the health department mandates that all wells must be 12 inches above final grade. Before the health department got involved, wells had no maintenance and were sealed in the ground with just a valve box put in place for the shut off. Wells constructed by Florida well Drilling are painted with an anti oxidation paint to prevent any premature corrosion since it in now open to the elements. and physical abuse from lawn maintenance. However, all wells should be painted yearly, if not maintain properly, rust can form; and in time develop a pin hole at the surface that will have to be repaired.
If you want to have a maintenance free well, you can consider having a cemented well sleeve installed. This will seal the top portion form moisture and the air, the two key elements needed for rust to occur. The sleeve goes down 18-24" below grade and all the way up to the shut off valve.