In vampire world, the rules keep changing

On HBO's True Blood (Sundays, 9 ET/PT), Lafayette asked vampire sheriff Eric to turn him. And Twilight found Bella Swan begging immortal beloved Edward Cullen to make her a vampire.

Before folks swear off sunlight, they should know the basics, which would be easier if the rules didn't change in every film, book and TV show.

USA TODAY offers a guide to life (and after).

	'True Blood'	'Twilight'	'Angel'
What just happened to me?	A vampire drained your blood and replaced it with some of his own; the two of you were buried together for a day to transfer his vampire's "essence" to you. Then you rose as a vampire.	A vampire bit you in several places, injecting venom that coursed through your veins, incinerating your organs and finally stopping your heart.	You got dialysis, vampire style -- you were drained and buried, and then drank from your sire.
This is like puberty all over again. What's going on?	It's an apt description. You've grown fangs, which pop out when you're aroused. You're also hungry all the time. And then there are those impulses. As Bill describes his new "daughter": "She has no humanity. She's in the grips of an overwhelming number of transformations. There will be times when she cannot control even a single impulse. … She is a loaded gun." Just like a teenager.	You won't grow fangs, but your eyes have changed from their old color to red. The hungrier you are, the darker they'll be. After feeding, they'll brighten. And because your hunger will be uncontrollable and because vampires are not out in the open, you must stay away from humans for the short term, especially family and friends.	Your fangs will pop and your forehead will bulge when it's time to feed or fight.
Besides immortality, what's in it for me?	Superhuman speed, lightning-quick reflexes, rapid healing of wounds and heightened senses of hearing and smell. Some vamps can fly, but not all. (In the books, Eric can but Bill can't.)	Everything the True Blood vamps get. Plus, many Twilight vamps assume a special power, like mind-reading or clairvoyance.	The usual speed, strength and sense enhancements. And say goodbye to your soul; you won't need it anymore. Just don't tick off any Gypsies, or they may give it back to you. That's no fun.
Am I locked into this look forever?	Your body will remain as it was when you were turned, so hit the gym beforehand. Also, physical problems will need to be healed by drinking vamp blood while human, or you're stuck with them.	Actually, you'll become even better looking. All four Twilight books are rife with descriptions of how gorgeous vampires are.	For the most part, but you can do things like cut your hair. Otherwise, Angel would still have the ponytail from his aristocratic youth in 18th-century Ireland.
Who'll teach me how to be a vampire?	Your sire (the vampire who turned you) is responsible for your instruction, which includes feeding, glamoring and controlling those pesky impulses.	Your sire is responsible for your guidance, and your level of assimilation with humans depends on him.	Angel adhered to the "you drain 'em, you train 'em" rule. Before Gypsies cursed him and took all the fun out of being a vampire, Angel (then Angelus) was quite hedonistic, a lousy role model.
Who's for dinner?	The synthetic TruBlood means you don't have to hunt humans for food. Blood banks are another option. But many vampires still prefer the real thing, at least part of the time.	If you join the Cullen coven, that means becoming a "vegetarian vampire." They hunt animals rather than people. But the hunger for the real thing never totally goes away.	Try pig blood. You'll like it.
Will I ever see the sun again?	Not if you want to live. Even a little bit of exposure will weaken you and cause your skin to blister. The longer you stay out, the more you risk burning to death.	You can go out in daylight, but unless you want everyone to see you sparkle like the counter at Tiffany, save your public outings for rainy or overcast days.	Yes, but don't go out without a heavy coat or hoodie and definitely don't look at the sun.
Can I be killed or commit suicide?	Beware of wooden stakes, sunshine and fire, all of which are deadly to the undead. For jaded vamps, the most common method of suicide is "meeting the dawn." And stay away from silver -- it burns vampire skin and can immobilize you.	You are still susceptible to decapitation and burning, as James found out the hard way in the first book and film. You may not kill yourself, but you can petition the Vulturi, a sort of Vampire Supreme Court based in Italy, to do it for you.	There's no coming back from staking, decapitation and burning. Sorry.