What is happening to the soil above the wall? How long is the slope
above it, and what is on it? Do you see any tension cracks in the soil
uphill from the wall? Are there any structures uphill? Is it possible
that the whole slope is moving slowly?

Are there any large or heavy structures uphill? Could anyone be injured
if it collapses? Would there likely be property damage? Or is it a
cosmetic or convenience problem? I would let my decision be guided by
those factors.

The retaining wall is perpendicular to the front of my house. It is
alongside my driveway, and separates my driveway from my front lawn. The
wall exists because my front lawn is around 3.5 feet higher than my
driveway, since my garage is basement level. My front lawn is relatively
flat, but since, over the years, the soil behind the wall has gone through
the weep holes, a small section of lawn that is immediately behind the wall
happens to be at a slightly lower level than the rest of the lawn and is
sloped downward toward the wall. We're only talking about section of grass
that is a foot or two behind the wall and is only sloping downard by say 6
to 9 inches tops. Other than that, there is no slope, and the only reason
there is a slope is because soil has gone through the weep holes over the
years.

If the wall fell (and, to me, it doesn't look like it's about to fall) it
would fall onto my concrete driveway, and would just be an inconvenience
unless this could potentially damage the concrete driveway.

Jeff