Got my hair relaxed for the 1st time

So about 3 months ago i got my hair relaxed/permed for the first time. After about 2 months I had a lot of new growth, so a couple of days ago, i got it re-relaxed. I have some questions about black hair being relaxed in general.

Just to give some background on my hair's health, I wash and condition it once a week, and apply moisturizer everyday after getting out the shower. I don't cover it up at all even when at home, but i'm going to start. The lady that re-relaxed it said my hair is nice and healthy.

Okay first of all, my mom and the lady that relaxed my hair said that i'm not supposed to wet my hair... What? Wouldn't not wetting my hair cause my hair to be dry and dandruffy?

Also, how often should i straighten it? Because i really don't like the way my hair looks when i don't straighten it at all after getting out the shower. I usually straighten as often as i can, which is usually about every other day.

And by the way, it is my understanding that i'll have to go back to the salon to get my newgrowth re-relaxed about every 2-3 months for the rest of my life... Right? :/
I mean if i have to do this i will but, damn. lol.

please dont wash ur hair everyday , only wash it every 3 days and use shampoo only 2 times a week and everything else will b fine . and if u gonna wash ur hair every 3 days u can straighten it also every 3 days .....