is 70 regular stim packs enough to survive ?

where can i get 10-40 more and have them restock every 48 hours ?

Worst thing is your head explodes...

There's no 40 stimpaks restock option LOL You can find casino chips around the Sierra Madre and then buy stimpacks from various machines around Dead Money. You will also learn how to make those chips yourself from one of your companions.

Also, you will arrive at the Sierra Madre withouth ANY of your stuff, so don't worry about how many stims you have right now.

All you stuff gets removed when you start the DLC. One of the reasons DM gets so much love and hate.

In the DLC stims are very scarce if you don't find the code that lets you buy them in the vending machines and you need to use predominantly pre-war food and water to heal.

Take it slowly and have fun but know when to let go

what do you mean let go ?

You're stuff is taken off you at the start. So stimpacks, weapons, etc are all got from the stinking hellhole that is the sierra madre.

So the only preparing you need to do is get rad resistant perk, radiation resistant or beneficial perks, and have a high endurance, if it works with your style. You need high medicine, speech, science, lockpick, survival, repair and a high combat skill. High barter might be a good idea too. If you are unarmed, melee, or explosive, investing a little in guns or energy weapons, might be a good idea. Also get chem resistant, and any perk that stops you getting hooked fast. No doctors about in parts and fixer can be hard to come by in parts of it.
Massive medicine, repair and science checks in it.
Basically go in at a high level with the skills you'll need high.

The ammount of stuff you find is the same as elsewere, so you can loot enough stuff.
And you can buy them with sierra madre chips from the sierra madre machines. You can also cook and craft stuff and make ammo.
You'll be fine for stuff.
I never had much trouble finding stimpacks, etc.

It's a phrase from the dlc. It's rather meaningless and gimmicking and repeaded far too often. 'Begin again and know when to let go' is in the transmission and part of the game.

1. Meaningless? I think that it's an important story aspect for every single character in Dead Money.
2. Only if you really focusing on that part, I barely notice it.