Roadster owners have had this discussion ad nausum, and nothing Tesla has said indicates that Model S is any different in these regards:
1) Keep the car plugged in whenever you can. That means even if it's charged.
2) Charge in Standard mode whenever you charge, as long as you don't need the extra range.
3) Charge the car every chance you get. If your commute is 5 miles, don't wait until the weekend to charge - charge every night. More light cycles better than fewer deep cycles.
4) Don't worry about charging the battery too quickly. Your Tesla is built to handle it. On Roadster, consensus is that 30-40amps (UMC max) is just about the most efficient. Going faster heats up the battery more, so it diverts juice to cool it, and charging slower provides no benefits. But, do not worry about 70/80 amp charging. Heck, SuperCharging doesn't hurt the battery.
5) If you need a Range charge, best to do a Standard charge first, then start the Range charge so that it completes about 15 minutes before you start your drive. That way the batteries don't sit completely full for long. Although Tesla will use wall energy to keep the batteries cool to reduce damage, doing that a lot will lead to quicker degradation. Note that leaving the car fully charged in Range mode once in a while is OK, and provides a benefit of battery balancing. But, keep the car plugged in when it's full in Range mode!
6) After a hard drive in hot weather, your battery may be warm or even hot, so even though your Tesla will cool the battery if it's really hot, the Tesla algorithms are compromises between battery life and power consumption. If it's not plugged in, your Tesla doesn't know if it's OK to use juice to cool the battery since you might want that juice for driving. So, it doesn't cool the battery down as much as is optimal for longest life. Therefore, after a spirited drive, it's best to plug the car in and charge right away since that cools the battery to a lower temp than otherwise.
7) If you're on a TOU meter, you may not want to charge as soon as you get home, even if the battery's hot. Doing a Range charge at 240volts, 13 amps for 20 minutes or so will force the car to cool down the battery but not use too much juice. When the battery temp drops below 80 degrees F manually stop the charge and reset charge mode to Standard. I use OVMS to monitor the battery temp and setup the charge modes on my Roadster.
8) It's just fine to have the car sit at full Standard charge while plugged in for weeks at a time. Roadster has a "Storage Mode" (Model S doesn't), but I've never heard any Tesla employee advise anyone to actually use it. Maybe if you're not going to drive the car for months or something.
9) Avoid letting the car sit at low charge levels for long periods of time. This may be more of a problem with Roadster than Model S, but if you can avoid it you should avoid it.