In my personal book of stuff, commendations and their ilk have generally leaned toward the side of useless. Ignoring how useful they actually are once you hit that mythical creature I have heard of but never seen, often called “end game,” the commendations you receive on the actual leveling path can range from highly useful to discarded and forgotten. This all banks on the prayer that the developer has made these commendations easy enough to obtain, and requires the player spend enough time in that zone, to obtain enough of that area’s commendations, before they outlevel the area and whatever reward said commendations might bring.
Currently in The Old Republic, commendations are planet-specific. So if you leave Hutta before you have any use of the Hutta commendations, odds are you probably won’t have any use for them in the future. With update 2.0, Bioware is condensing all of the planet-specific commendations into one wallet-sized credit card. Alongside planetary commendations, players will be able to obtain Classic (level 50 flashpoints/operations), Basic, Elite (level 55 flashpoints/operations), and Ultimate (Hard/Nightmare Mode) commendations, each with their own cap on how many can be obtained and stored.
Darth Hater notes that the planetary commendation cap is 100, as opposed to the thousand per planet currently in-game.
(Source: Darth Hater)