How does the rested experience system work?

When I first started playing Star Wars: The Old Republic, I was pleased to see a rested experience system in place. I had made extensive use of it in World of Warcraft, and planned to do the same here. I was quickly disappointed to learn that all of my rested experience was eaten up after a short few quests. Not a dealbreaker, but disappointing.

Fast forward a few planets, and I'm now in the high-20's for levels. I also can't seem to use the rested experience up at all now. Not complaining, but I don't do anything out of the ordinary (log off in Cantinas is about it) and just can't use it up fast enough!

How do the mechanics of the rested experience system in Star Wars: The Old Republic work?

Rested XP doubles all combat kill xp. It does not double exploration, quests, PVP, etc.

There are two ways of gaining rest XP in SWTOR.
While logged off you gain a small amount of rested xp. This amount is the same regardless of where you log out.

In addition, anytime you are in a "safe area" (most cantinas, fleet, your ship) you gain rest XP. The two ways of gaining rest XP stack if you log out in a safe area.

Your maximum rest XP is equal to the total amount of XP needed to get through your current level.

While in a "rested" state, you gain double experience for any kills made. You don't get double experience for space combat, mission rewards or PvP Warzones.

I think, but can't confirm at the moment, that this also affect Legacy XP.

You can get rested XP to cover up to one level. So if you play for extended periods of time, you'll quickly pass the rested XP amount. Once your level is up to a certain point, and each level lasts a few days of your play time (obviously depends on the amount you play), then you'll probably remain in a permantent state of rest. I haven't left rested state since around when I hit level 20.

You rested experience bar goes up when you log off in "safe areas". This includes your ship, the faction fleet and as you say, cantinas.