Depends on which customer you're talking to. Most will be fine with that. I think about a week is considered standard. A few will think that is woefully inadequate, and threaten to spend the rest of their days on earth, trying to drag you into financial ruin, through bad reviews on every review site they can find. ;-)
Seriously, I've found that most people are fine with about a week. After that, you start getting the emails sometimes. But that can be avoided by just being honest up front, on the ones where you know it will be longer, or close to longer. Most reasonable people just want honesty... Not placating. But you will always have the few grumpies that will never be happy no matter what. Suck up, tell them you're sorry and move on.
The issue you have to be mindful of, is not so much the time it takes to get there, but how they react to the 'shipped' notification. Say that you ship using priority. That gives you wiggle room. That will often get there day after next during week days, even if it's across the country. Ground... Much longer. So say you get an order Monday and wait until Friday to ship. Good chance it will still get there Monday on priority. So one week... Most people fine with that. Now say you did the same, but they get the shipping notification that it just went out on Friday, after they ordered Monday... Some people are going to flip out over that. Yes, makes no sense... It will get there in the same time as if you shipped right away and used ground. But people make assumptions, and for some reason the idea that it took 5 days to ship can set some people off... Even if the end result is the same.