Most of the parts involving water are either brass or teflon with rubber or teflon o-rings. Both of which are soft materials and will eventually wear down to the point of leaking. Preventative maintenance is really the only thing you can do...replacing o-rings and cleaning/polishing parts. Wear time is also determined by your water type. If you have good clean water your, wear time is extended. If you have fair or poorly cleaned water and debris is commonly found, your wear time is dramatically cut down. These are soft materials your dealing with so its always going to be a bit challenging at times to keep them in good working order. You cant really grease anything because the water will wash it off, so water is basically your only lubricant...which its a very poor one. Quality of product and warranty will help alleviate some of your headache. Its just a part of being a good home owner to keep up with your appliances.
One ting I hear a lot is "...it never sue to do that before with my old system...". Well, its been proven that todays products are (for all intents and purposes) crap. Things aren't built like they use to be. Delta is a good brand name but just look at what they are built with and what your asking it to do. The older setups where changed for there reasons (probability for safety and efficiency reasons) and the older models most likely had years of crud and water junk built up top prevent leads from occurring. It doesn't mean you have a bad system just because it leaks consistently, but apply common sense and see if its worth your time and money. Consistency wear and tear is not necessarily a bad thing, it can be annoying at times though.
