How much maintenance you’re willing to do may be a determining point in which hardscape product you use.
Here’s a general guideline of materials and upkeep:
Need to be washed annually
A sealer should be applied about 6 months after the foundation is put in and every 2-3 years after so it doesn’t get discolored or stained.
No sealing required.
Unless they’re in concrete the stones need to be checked in case they’ve moved.
Inspect annually for rotting, splinters and loose screws.
Power wash and seal annually to help prevent discoloring.
No sealing, painting or staining is necessary.