I am paranoid and I do not want to make any mistakes.
My NSRs are scattered over 30 addresses.
I would like to clean up and put them into 3 addresses, only.
I can think of 2 ways:
What is the best way?
And what happens to my coins age in each case?
Tks a lot for your help.
If you move your coins, you will reset coinage. I’d suggest you make a new address and simply send your wallet balance to that address. Note that you’re gonna pay a boatload of fees for all those inputs (probably less than 10 nsr).
How do you have nsr at 30 different addresses? Are you sure it’s not at 1 address with 30 different outputs? The wallet autochunks nsr into 10,000 nsr groupings.
Tks for your answer.
Right. There are addresses among the 30 that are outputs but I did create more than 10 deposit addresses in the past.
The end goal is to print out the encrypted private keys of my wallet.
I d like to limit the number of keys to 3.
Based on your suggestion, I will create 3 new addresses and send my NSRs into those 3 addresses and wait 7 days before being able to mint again. This was my idea as well but I wanted to get a second opinion. 
What about the stake? I cannot send the stake right now. I guess I would need to wait till the staking is consumed, before being able to send it as a part of the balance (before it gets into the balance), right?
EDIT: What is the fastest way to unfreeze the staked balance? Sorry for asking so many questions.
The stake created when minting a block needs to have 5,020 confirmations before it can be spent (which would under normal circumstances be approximately 3.5 days).
I see. Tks. So if I want to spend the NSRs indicated under the Stake field in the Overview option in QT, I need to stop minting and wait for 3.5 days roughly?
Yes, you need to wait.
But you don’t need to stop minting - after they reach a spendable state it would require even more time before they could mint again (depending on difficulty);
if you send them once they are spendable, everything is fine.
In case you don’t want to risk anything (e.g. having some of the outputs mint again 
), stopping the minting is the safe way.
Tks for the piece of advice.
I am gonna stop minting and wait a few days and verify that my stake is decreasing.
You are experiencing the point of PoS: once you verify a block (i.e. mint) your funds are frozen for a few days to prove you have a stake in the verification process.