Oddly enough, sometimes letting things fail is the cheapest way to create a better design. Not necessarily in direct costs, but getting a great product out in 30 years is rarely an option.
Has SpaceX actually cleaned out and reused any of their recovered rockets yet? I'm guessing no, they're still analysing them, but it'll be interesting when they do. (Damned if I'd want my payload on the first recycled rocket...)
remember to always take Elon's time preditions with caution, he originally said CRS8's booster (the first landing on the ASDS) would be ready for flight in "june, maybe july"
I'm sure they're doing their best, but space takes time.
"space takes time" is pretty good. Understood they could miss the date, but that's what Elon said they're targeting. If the first re-use is October 2017, I'll still be impressed as I'll bet the timeframes compress over time.
A re-used rocket should be more reliable than the first go-around. Purely because if anything is likely to go wrong it will either happen on the first run or after N runs that is enough to wear a component out. N is likely much greater than 1.
That may be true in the long term, but that may not be true for the first few attempts until they understand the sort of things that are stressed/weakened/generally affected by the first launch.
unless some significant wearing happens during descent
That's the hope, but we don't have enough experience to know whether or not it's true. The analogy people like to use is airliners, but airliners don't get anything like the g-forces or heat load you see on a returning rocket stage.