Teen 'zines, dress sellers, even high school newspapers are hawking the dreaded Prom Checklist, detailed enough to make even the most obsessive teenager feel inadequate.

The funniest? Try "Four months before prom." In teen years, that's like three marriages and two divorces.

About a month before his April prom, Dan Fong will pop the question. The Kailua High senior said that for some, the timing is tied to a window of opportunity: "You have to buy the bids early."

If your date is either completely assured or as interchangeable as the vintage Mystery Date game fella, you might plan further ahead. On these laid-back shores, with prom season starting in March, it's weeks rather than months.

Yes, you can cut a better deal on limos and so on if you shop ahead. And ladies, while it's good to book your hair and nail appointment early, what really needs to be done when?

SOONER RATHER THAN LATER:

1. Ask her/him and get a firm "Of course!" (Sad truth: If she/he needs too much time to think about it, she/he is hoping for another invite. Practice saying: "It's OK if you want to think it over. If I don't hear from you by next week, I'll take it as a no. But thanks for considering it.") Oh, and get the 'rents in on the plan. You don't want them to expect you home before 2 a.m. if you're planning otherwise.

2. Make a budget. How much can you wrangle from dad for a shared limo by insisting you can't possibly drive home from Waikiki at 2 a.m. in the family minivan "with all those drunks racing each other on the H-1"? Truckloads. As soon as you have that budget, line up the transportation and other reservations.

3. Buy (or if you're on a budget, borrow) clothes, accessories, shoes. While some girls have been sketching their look since freshman year, others see beyond a single closet. Have you been lusting after your cousin's Zac Posen clutch? No way she'd turn you down for a prom loan. And many a girl has wished she'd gone an extra mile for comfort as well as beauty in her prom shoes, unless she kicked them off in favor of rubber slippers as soon as the dancing started. Oh, and if Auntie knows how to do flowers, that's a chance to save some bucks.

GUYS, BEFORE SHAVING:

1. Try on your actual outfit, in full, in front of a critic. You don't want to find that brown socks don't go with the black shoes.

2. If you're driving, detail and fill up Dad's pickup. This is one night he's not going to buy the "we ran out of gas" line.

3. Get flowers. Really. Even if you're having Auntie make them. Even if you're color-blind. You won't believe the mileage you'll get from "These puakenikeni remind me of you."

LADIES, BEFORE THE MANI-PEDI:

1. Test-drive the hair and makeup. Go for a jog in it. Do yoga. Wash the dog. There's no marathon to compare with prom night, and there will be photographic evidence.

2. Try on the dress with the proper undergarments. Sometimes, it takes longer to find the right bra than it does the right dress.

3. Charge up the cell phone. 'Nuff said.