I didn't think it was confusing, but okay...

1. Most of the time I can't get through an entire shower (10 min.)
with enough hot water.
2. A couple of times it wasn't even hot to start out with (!!)...that
is, I had to shower with the cold turned off from the start.
3. I *think* the problem has become more frequent.
4. 40 gal., 40,000 BTU gas water heater. 5 years old? Just a
guess...bought the house 1.5 years ago. Manuf. date is 1996. Can't
see the inside, but the outside looks mint.
5. Drained the tank last week....got some sediment and some slimey
blobs.
6. Pulled the dip tube yesterday and verified it's in perfect shape.
7. Thermostat is set on the tick after "HOT". No numbers.
8. I'm 5'11", I like long walks on the beach, Frank Sinatra songs...

Mike