They have more energy longer as they become more physically fit. Also rewards like 'steel bladder' and 'dirt defiant' are my first reward purchases, at first it seems your whole day is consumed with the drugery of shower/eat/sleep/toilet.
Different traits also affect needs-social butterfly is one I stay away from they- always need social interaction.
There is kind-of a cheat head start: When creating sims make their lifetime wish 'living in the lap of luxury' (you can choose any career later anyhow) and then 'motherlode' 100k and they get 30,000 reward points right then...which you can spend on 'steel bladder' and 'dirt defiant' with some left over. next save up and get 'fast learner 15k, or 'no bills ever' 15k, (note: only one person in the household needs to purchase no bills ever) and then the trump- 'hardly hungry' 25k! with those, a good bed, and some fitness, all you have to do is have fun and social, both of which I found are raised quickly in the hottub.and hygiene!
*EDIT- I did some more search on Lifetime Rewards Points, i thought I read somewhere of a cheat for rewards (theres a cheat for everything else) well heres the link. be sure to follow her instructions exactly, iow: type in testingcheatsenabled true before clicking on the family play button. then it works but you have to hold down CTRL while clicking ;>
http://forum.thesims3.com/jforum/posts/list/42691.page#347560
