As was mentioned just turn the power off when you are not going to be
there.

My wife always starts the dishwasher just before we leave, so as to not
waste the remaining hot water, so we kinda need the power. I can't have my
cake and eat it too; maybe turning off the power (or at least the well) is
better than saving a little electricity/hot water.

I would install a simple sediment filter on the water line they are
inexpensive and do save lots of headache with clogged aerators it will
also
tell you if you are sucking sand which does happen.

There are filter on it now, but the water heater is apparently still full of
old debris that no amount of flushing seems to eliminate completely.