Rick,
I have had some good battery experience and find about four years life is
what you can expect.
If you take care of your battery it should hold enough reserve power after a
start to give you that thirty minutes we all need after the alternator
quits.
The new technology trickle chargers sound like a great thing tho I have no
direct experience.
The very worst thing you can do is run the battery dead.  These are not deep
cycle types.  They loose a good percentage of their life each time they are
"killed".
Add to that putting in too much distilled water and watching your baby
overflow on the charger and you have a big waste of bucks.  Read and follow
the charging directions!
I am using my first Concord RG (recombinant gas) battery in our IV-P.  I
installed it eighteen months ago to cycle the gear and such.  It seems to be
just great so far.  I have done no capacity check yet but I'm not worried.
I charge it every sixty days when it's out of use.  I firmly believe the
RG's are the wave of the future.
Best luck,
Walter Dodson   IV-P  87%+/-