I am new to the business too (7 months) but might be able to help you out a bit since I just finished an RO install. I learned a lot here on the forum and by contacting Dultmeier, who is the manufacturer of my system.
One thing I was told is that you shouldn't run an RO system if your Softener is not up to par. Anything less than 1 grain of hardness making it past your softener will eat away at your membrane. I guess this falls under your maintenance question. You'll need to start by checking the total grains of harness before and after your softener to see where its at. Mine is about 2 grains before and less than 1 grain after the softener. Another thing I was told, is there can't be any chlorine that makes it to the membrane of your RO unit. So you'll need to check for chlorine after your Carbon filter. A simple pool test kit will get this job done. You should also have a pre-filter to filter any solids before making it to the membrane. Mine is a 5 micron filter. This should be changed monthly. More if used heavily. Lastly, I check my RO water pretty often to check for TDS. (Total Disolved Solids) With a new membrane, mine runs less than 5 tds. The Dultmeier engineer said that a membrane that has hardness free and chlorine free water going to it will last many years, depending on volumn. Allowing chlorine or hardness to get to the membrane shortens its life considerably. Anything over 40 tds and your membrane should be replaced. This is all from the Engineer at Dultmeier...
As far as the resin price goes, just for comparison, Dultmeier has is for $72 per cubic foot. Somebodies wanting to make up for losses in the stock market!
Hope this helps...
Jeff
