Ya that is a big factor. Like everyone that has a RO unit knows filter changes are very important. I'm not sure of how often they have service performed.
I know a few people that use the Tap water purifier. It is a less expensive way to get good water. In the end you will pay more but Less than the home delivery way.
Here is the link to J&L's they sell the unit for $59.95
http://www.jlaquatics.com/cgi-bin/sh...logno=ro-aptwp
Also on Ebay.ca
nice RO/DI unit
http://cgi.ebay.ca/ws/eBayISAPI.dll?...301160453&rd=1
J