I have been seeing videos that the plan after Perseverance is done collecting samples to distribute them in 'strategic' locations around Mars for another rover to drive around and pick up later. Why isn't the plan to leave them inside the rover or place in a special container for the other rover to pickup?
I don't feel comfortable being skeptical of a well thought out NASA mission, but Mars is a giant desert with huge dust storms. I have a hard time believing that the next rover won't have a hard time trying to get to samples buried in dust. Maybe some can be retrieved, but all?
Several animations of "disappearing" artificially-induced features on Mars' surface over a period of years can found at https://www.jpl.nasa.gov/images/changes-in-scars-from-2012-mars-landing