I believe that optimization is important enough for you to know, and be aware of, in the beginning. You are going to do some awesome work and I don't want you or your stakeholders to think it's any less awesome, or slow, or anything else because you didn't know the tricks to squeeze maximum performance out of your systems. It's never too early to impress people with the performance of your creations. Mobile is a very unforgiving environment and some of the tips in this section will make more difference than any of the best coding practices.

From a performance perspective, there is absolutely nothing worse than an HTTP request. That's why CSS sprites are a good idea. Every request we make slows us down because the TCP/IP protocol assumes that each request's available bandwidth starts somewhere near zero. Not only do we have the initial delay in pulling assets from the server, there is also a ramp-up time before that asset is transmitted...