I think I may sort of already know the answer to this question, but I want to ask it anyway. My original chain (Ultegra I think) made it to 3,000 miles. I just had it replaced again today and the second chain only made it 1,350 miles. Does this seem reasonable?

I kind of think it makes sense, because the cogs and chainrings are undoubtedly wearing down and the second chain probably wore out faster because of this. I ride hilly terrain so I do tons of shifting and use nearly all of my gears. But I'm really good about cleaning and lubing things...I may even be a little OCD about it. So I would guess that the next time I need a new chain, I'm also going to need a new cassette and chainrings. But I hope this chain lasts at least 1,000 miles. Or do I need to start shopping for a deal on a new cassette & chainrings now?