Ledger nano - new btc addresses ?

[bosshyip]

Hi guys
It's that time of the month again to buy some BTC.  I realized my ledger suddenly shows new public keys for me to recieve btc to. I did a test and sent myself 40 cents to my old address, and then again to the new one. The incoming and outgoing addresses were still my old public key.

And yes BCASHers, its possible to do that on bitcoin, I even sent one at 1sat/byte.

I know that one private key can generate more than one public key. 
My question here is, is it fine to save one of these public keys and use it as a receive address permanently? Will my ledger just create a new receive address each time funds are received that is usable for privacy reasons ?

Only had this thing for a few weeks now, so im new to these kinds of wallets.

P.S. I see unconfirmed transactions are quite low today, I can turn all my inputs into one input by sending my BTC to myself right ?