SEL precautionary landings: what's your experience?

Got 20 min away from the airport, heard something knocking, turned
around and went home. Decided that if I had to land someplace other
than the airport, I'd rather be going towards the airport and
following the interstate rather than continuing on, when I knew that
my airport was considerably closer than the next one towards my
destination. Mag cover had come loose and was rattling.

Coming home from NM to Denver (night) following I-25. All of a sudden
I couldn't see the lights of Denver (just south of COS with clear
vis). Called COS and requested vectors, landed, borrowed the crew car
and drove home (about an hour). Came back the next morning, dropped
the crew car and flew home.

Finished runup, got cleared for takeoff. Rolling down the runway,
called the tower and stated I was cancelling takeoff. (You can do
that real easy at an airport that doesn't have lots of traffic.)
Serious shimmy on nose wheel, so much so that I felt that there
would be a possible danger when landing later on.

There have been numerous occasions when I decided I didn't like the
weather, despite DUATS and FSS. About 90% of the time, I'm right. The
other 10%? So what? 9-1 odds are really good!