There are several factors than can affect the life of a pressure regulator.
Is the new reg the proper pressure rating ? I have seen city water pressure as high as 140 , a pressure reg only rated at 110 or 150 will have a shorter life than one that is rated for 200.
Is the regulator sized for the proper flow? Having a regulator that has smaller orifices can be an issue if your usage with hoses is 10 gpm make sure the reg can handle the flow,
In large homes many times I might put a 1-1/2” reg on a 1-1/4” line so the reg is tot the limiter but the larger orifices in the reg reduce the chances of failure.
Was it a cheap regulator? Like many things there are quality components that can cost over 2x but can be worth it.
Now something to help your next regulator have a longer life.
Add a string filter or metal mesh clean out prior to the regulator, the string or metal mesh catch small bits of rust scale even sand from filters and prolong the life, yes you may need to clean the mesh Y clean out or replace the string filter but this is less expensive than a new regulator, the mesh y clean out doesn't cost anything.
So it may be normal if a cheap model or the supply has a lot of scale , rust or grit.