Timeliness is a critical part of creating a successful customer experience. As a business keynote speaker, I'm often heard calling on company and conference audiences to remember the key principle of timeliness:
A perfect product, delivered late, is a defective product.
But what does "late" mean? To throw a few ugly words at it, what I'm really talking about here when I say "late" is "on a timetable that diverges negatively from what the customer expects."
So, that brings up the question: how much time have you spent figuring out what the customer expects? Here are some of the factors which create their expectations:
The norms within your industry
The norms outside your industry (sorry, everyone, but Amazon.com has changed the whole timetable game in a huge way, regardless of the service or product you in particular offer)
The customer's experience with your company on prior transactions (all those "good news! we've upgraded your shipping to overnight!" notices from Zappos eventually create a new norm for their repeat customers).
The information you convey to the customer, when you convey it, and how you convey it (did you call her back immediately to let her know there might be a delay? This in itself can positively affect the customer's perception of your timeliness–as opposed to waiting 4 days and saying "tah dah, we're done!")
The details of the waiting experience. To a solitary diner, for example, every wait between courses will seem notably longer than it will to a couple engaged in happy chatter. So offer reading materials, check in more often, and otherwise mitigate these perceived delays.