Beauty & body questions?

Can anyone tell me anything about any of these?

1. leg waxing – how long do you have to let the hair grow for? how much does it hurt first time?

2. st tropez or spray tan? how long do they last before you have to top them up if you get them done professionally. if it's for a special occasion how many days in advance would you advise getting it done?

3. do any work out dvds work? i work shifts so can't really do any classes with my friends and figured that would be an ok alternative.

4. how do i stop myself biting my nails? and are there any things that make them grow quicker.

5. looking after my skin – exfoliater, cleanser, toner, moisturiser – which ones are good? i know i need to eat more fruit and veg and drink more water.

6. is there anything good for making stretch marks dissapear?

thanks