Lanman1978
Android Enthusiast
This is something that I highly suggest doing because it can really speed up your ROM. As a matter of fact there is an app that takes all the work out of it, the Kuban Odexer. Of course you need root and busybox/init.d in order to run it. Oh and a word of caution just in case anything goes wrong make a backup of your ROM before you run the odex process. I just odexed two ROMs in the past few days and it went off without a hitch both times, but it pays to have a good backup just in case.